ChemWiki - User contributions [en]

Rep:Mod:imperial123

2014-10-23T16:38:54Z

Hc2711: /* Benzene */

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

v = frequency (cm-1)

k = force constant (Ncm-1)

μ = reduced mass (kg)

The force constant is relative to the strength of a bond. The bond in a BH3 molecule is shorter than the bond in GaBr3 and is therefore stronger. Therefore, there would be a larger force constant value, which in turn causes there to be a larger frequency value. Additionally, the reduced mass value is relative to the molecular mass of the molecule in question. BH3 is a lighter molecule than GaBr3 and would therefore have a smaller μ component. As a result, this would also increase the frequency value of BH3 relative to GaBr3

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

==Questions==
'''What is a bond?'''

A bond is an attraction between atoms as a result of sharing electrons in order to form substances that contain two or more atoms. The electrostatic attraction forming a bond can be a result of attraction between oppositely charged ions, between electrons and nuclei or due to a dipole attraction. The bond will only form a stable molecule if the total energy of the created compound has a lower overall energy than the separated substituent atoms.

'''How much energy is there in a strong, medium and weak bond? Give examples of each type of bond (strong, medium and weak)'''

A typical strong bond is the nitrogen-nitrogen bond in an N2 molecule. This is around 945kJmol-1. An example of a medium bond is the bond between a carbon atom and a chlorine atom; this has a bond enthalpy of 331kJmol-1. An example of a weak bond is an iodine-iodine bond which has a bond dissociation energy of 151kJmol-1.

'''In some structures gaussview does not draw in the bonds where we expect, why does this NOT mean there is no bond?'''

In order for a bond to be graphically depicted in the expected position, the distance between the atoms must be within the range that is programmed into gaussview. If it is not in this pre-programmed range then the bond would not be drawn where expected. This does not mean that there is no bond as there is a wide variety of bond lengths due to the wide variety of possible molecules.

'''Why must you use the same method and basis set for both the optimisation and frequency analysis calculations?'''

The basis set and methods must be the same for the calculations. The method is related to the LCAO part of an equation and the basis set is related to all of the functions used. If at any point of the calculations one of these is not the same then the results will not be valid.

'''What is the purpose of carrying out a frequency analysis?'''

Frequency analysis is useful in determining whether the stationary points derived from optimising the structure is a minimum or a maximum. The frequency analysis is the second derivative of the potential energy surface. If the value is positive, then a minimum has been obtained. If it is a negative, then a maximum has been obtained. However, if all of the values are negative then it indicates that the optimisation done is not the lowest energy state of the molecule and should be redone.

'''What do the "low frequencies" represent'''

A molecule with N atoms has 3N-6 number of vibrational modes. The low frequencies are indicated by the "-6" part of the equation. These frequency values are much lower than the first vibrational mode as they are the motion of the centre of the mass of the molecule.

==Aromaticity==
basis set 6-31g (d,p)

freq, MO

draw orbitals on diagram from gauss

b(benzene) + n(benzene) same thing no MO

compare

==Benzene==
[[File:Hc2711 benzene optimisation.png|thumb|A summary produced by Gaussian of an optimised benzene molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000212 0.000450 YES
RMS Force 0.000085 0.000300 YES
Maximum Displacement 0.000991 0.001800 YES
RMS Displacement 0.000315 0.001200 YES</pre>

The optimisation file is linked to via clicking [[Media:HC2711 BENZENE OPTIMISATION.LOG | here]]

<jmol><jmolApplet>
<title>Benzene optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 benzene optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

File:Hc2711 benzene optimisation.mol

2014-10-23T16:38:33Z

Hc2711:

File:HC2711 BENZENE OPTIMISATION.LOG

2014-10-23T16:38:05Z

Hc2711:

Rep:Mod:imperial123

2014-10-23T16:37:36Z

Hc2711: /* Benzene */

Rep:Mod:imperial123

2014-10-23T16:36:58Z

Hc2711: /* Aromaticity */

File:Hc2711 benzene optimisation.png

2014-10-23T16:36:28Z

Hc2711:

Rep:Mod:imperial123

2014-10-23T16:16:27Z

Hc2711:

Rep:Mod:imperial123

2014-10-23T16:13:15Z

Hc2711:

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

v = frequency (cm-1)

k = force constant (Ncm-1)

μ = reduced mass (kg)

The force constant is relative to the strength of a bond. The bond in a BH3 molecule is shorter than the bond in GaBr3 and is therefore stronger. Therefore, there would be a larger force constant value, which in turn causes there to be a larger frequency value. Additionally, the reduced mass value is relative to the molecular mass of the molecule in question. BH3 is a lighter molecule than GaBr3 and would therefore have a smaller μ component. As a result, this would also increase the frequency value of BH3 relative to GaBr3

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

==Questions==
'''What is a bond?'''

A bond is an attraction between atoms as a result of sharing electrons in order to form substances that contain two or more atoms. The electrostatic attraction forming a bond can be a result of attraction between oppositely charged ions, between electrons and nuclei or due to a dipole attraction. The bond will only form a stable molecule if the total energy of the created compound has a lower overall energy than the separated substituent atoms.

'''How much energy is there in a strong, medium and weak bond? Give examples of each type of bond (strong, medium and weak)'''

A typical strong bond is the nitrogen-nitrogen bond in an N2 molecule. This is around 945kJmol-1. An example of a medium bond is the bond between a carbon atom and a chlorine atom; this has a bond enthalpy of 331kJmol-1. An example of a weak bond is an iodine-iodine bond which has a bond dissociation energy of 151kJmol-1.

'''In some structures gaussview does not draw in the bonds where we expect, why does this NOT mean there is no bond?'''

In order for a bond to be graphically depicted in the expected position, the distance between the atoms must be within the range that is programmed into gaussview. If it is not in this pre-programmed range then the bond would not be drawn where expected. This does not mean that there is no bond as there is a wide variety of bond lengths due to the wide variety of possible molecules.

'''Why must you use the same method and basis set for both the optimisation and frequency analysis calculations?'''

The basis set and methods must be the same for the calculations. The method is related to the LCAO part of an equation and the basis set is related to all of the functions used. If at any point of the calculations one of these is not the same then the results will not be valid.

'''What is the purpose of carrying out a frequency analysis?'''

Frequency analysis is useful in determining whether the stationary points derived from optimising the structure is a minimum or a maximum. The frequency analysis is the second derivative of the potential energy surface. If the value is positive, then a minimum has been obtained. If it is a negative, then a maximum has been obtained. However, if all of the values are negative then it indicates that the optimisation done is not the lowest energy state of the molecule and should be redone.

'''What do the "low frequencies" represent'''

A molecule with N atoms has 3N-6 number of vibrational modes. The low frequencies are indicated by the "-6" part of the equation. These frequency values are much lower than the first vibrational mode as they are the motion of the centre of the mass of the molecule.

==Aromaticity==

Rep:Mod:imperial123

2014-10-23T16:12:44Z

Hc2711: /* Questions */

Rep:Mod:imperial123

2014-10-23T15:48:08Z

Hc2711: /* Questions */

Rep:Mod:imperial123

2014-10-23T15:47:51Z

Hc2711: /* Questions */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

v = frequency (cm-1)

k = force constant (Ncm-1)

μ = reduced mass (kg)

The force constant is relative to the strength of a bond. The bond in a BH3 molecule is shorter than the bond in GaBr3 and is therefore stronger. Therefore, there would be a larger force constant value, which in turn causes there to be a larger frequency value. Additionally, the reduced mass value is relative to the molecular mass of the molecule in question. BH3 is a lighter molecule than GaBr3 and would therefore have a smaller μ component. As a result, this would also increase the frequency value of BH3 relative to GaBr3

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

==Questions==
'''What is a bond?'''
A bond is an attraction between atoms as a result of sharing electrons in order to form substances that contain two or more atoms. The electrostatic attraction forming a bond can be a result of attraction between oppositely charged ions, between electrons and nuclei or due to a dipole attraction. The bond will only form a stable molecule if the total energy of the created compound has a lower overall energy than the separated substituent atoms.

'''How much energy is there in a strong, medium and weak bond? Give examples of each type of bond (strong, medium and weak)'''

Rep:Mod:imperial123

2014-10-23T15:43:52Z

Hc2711:

Rep:Mod:imperial123

2014-10-23T15:42:22Z

Hc2711: /* GaBr3 frequency analysis */

Rep:Mod:imperial123

2014-10-23T15:36:45Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

v = frequency (cm-1)

k = force constant (Ncm-1)

μ = reduced mass (kg)

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:36:33Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

v = frequency (cm-1)
k = force constant (Ncm-1)
μ = reduced mass (kg)

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:35:43Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=(1/2π)(k/μ)0.5

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:34:24Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>\tfrac{1}{2π}\times\tfrac{k}{μ}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:32:14Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>\tfrac{1}{2π}\tfrac{k}{μ}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:31:13Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>\left ( \frac{1}{2π} \right ) \left ( \frac{k}{μ} \right )</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:29:49Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>\left ( \frac{1}{2π} \right ) \left ( \frac{k}{μ} \right )</math

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:29:33Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

\left ( \frac{1}{2π} \right ) \left ( \frac{k}{μ} \right )

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:28:11Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math> \tfrac{1}{2pi} \tfrac{k}{μ} </math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:27:55Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>\tfrac{1}{2pi}\tfrac{k}{μ}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:27:42Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=<math>\tfrac{1}{2pi}\tfrac{k}{μ}</math>^0.5

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:27:24Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>v=\tfrac{1}{2pi}\tfrac{k}{μ}^0.5</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:26:29Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

<math>v=\tfrac{1}{2pi}\tfrac{k}{μ}0.5</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:25:48Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=<math>\tfrac{1}{2pi}\tfrac{k}{mu}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:25:22Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=<math>\tfrac{1}{2pi}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:24:04Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=<math>\tfrac{1}{2π}</math>(<math>\tfrac{k}{μ}</math>)<math>\tfrac{1}{2}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:23:34Z

Hc2711: /* GaBr3 frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre> Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

There is a large difference in the value of the frequencies for BH3 compared to GaBr3. This can be explained through understanding of how the frequency value is generated.

v=<math>-\tfrac{1}{2π}</math>(<math>-\tfrac{k}{μ}</math>)<math>-\tfrac{1}{2}</math>

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:17:28Z

Hc2711: /* BH3 frequency */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:17:11Z

Hc2711: /* BH3 frequency */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule. As shown in the table above, the vibrations at 1163cm-1, 1213-1 and 2715-1 are associated with a dipole change in the molecule and would therefore record a peak in the IR spectrum. As a result, there are 3 peaks seen.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:15:47Z

Hc2711: /* BH3 frequency */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715
|126
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:15:35Z

Hc2711: /* BH3 frequency */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber cm-1 || Intensity || IR active? ||type
|-
|1163
|92
|yes
|bend
|-
|1213
|14
|slight
|bend
|-
|1213
|14
|slight
|bend
|-
|2582
|0
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715
|126
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:14:33Z

Hc2711: /* BH3 frequency */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

In the IR spectrum, we only see three peaks despite the fact that there are six vibrations. This is due to the fact that in order for a vibrational mode to be IR active and show a peak in a spectrum, it must be associated with a change in dipole moment of a molecule.

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:10:54Z

Hc2711: /* EX3 section */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

The table above indicates that there is variations in bond lengths for each molecule. The reason for the differences is due to the size of the atoms in the molecules; namely the central atom (B or Ga) and the adjoining "ligand" atoms (H or Br).

Hydrogen is a small atom as it only contains one proton and an electron and therefore has a small 1s orbital; as a result, it can be situated much closer to the central atom without causing steric interference. Furthermore, having only one electron amplifies this idea as there is less electron-electron repulsion and therefore the bond length to a hydrogen atom would be smaller than that to a bromine atom. Bromine is a larger atom, with larger p orbitals that are used for bonding. As a result of this, the bromine atom is further away from the central atom in order to minimise the energy and stabilise the molecule. This difference is highlighted through the comparison of BH3 and BBr3; the bond length for the bromine containing molecule is larger than the hydrogen containing molecule.

On the other hand, changing of the central atom also has an effect on bond length. Gallium is a 4th row element and is much larger than boron which is a 2nd row element. The larger gallium atom means that the ligands associated with the central atom are not able to be as close otherwise there would be steric and electric interactions (as mentioned above) that would cause an unfavourable interaction. This can be seen through comparing BBr3 and GaBr3; the gallium containing molecule has larger bond lengths than the boron containing molecule.

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-23T15:02:32Z

Hc2711: /* EX3 section */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19Å|| 1.93Å || 2.35Å
|-
| θ(X-E-X)|| 120° || 120° || 120°
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-17T14:27:40Z

Hc2711: /* NH3BH3 optimisation and frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Optimisation===

[[File:Hc2711 nh3bh3 optimisation.png|thumb|A summary produced by Gaussian of a frequency analysis of an optimisation of BH3NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000123 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000515 0.001800 YES
RMS Displacement 0.000296 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 NH3BH3 OPTIMISATION.mol </uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3BH3 OPTIMISATION.LOG | here]]

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

File:HC2711 NH3BH3 OPTIMISATION.LOG

2014-10-17T14:27:11Z

Hc2711:

File:HC2711 NH3BH3 OPTIMISATION.mol

2014-10-17T14:26:41Z

Hc2711:

File:Hc2711 nh3bh3 optimisation.png

2014-10-17T14:24:33Z

Hc2711:

Rep:Mod:imperial123

2014-10-17T14:23:24Z

Hc2711: /* Frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

===Frequency analysis===

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-17T14:23:13Z

Hc2711: /* NH3BH3 optimisation and frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

=Frequency analysis=

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

Rep:Mod:imperial123

2014-10-17T14:22:54Z

Hc2711:

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

freq

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

The frequency analysis file is linked to via clicking [[Media:HC2711 NH3BH3 FREQUENCY.LOG | here]]

File:HC2711 NH3BH3 FREQUENCY.LOG

2014-10-17T14:22:12Z

Hc2711:

Rep:Mod:imperial123

2014-10-17T14:22:03Z

Hc2711:

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

freq

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

<jmol><jmolApplet>
<title>BH3NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711_nh3bh3_frequency.mol </uploadedFileContents>
</jmolApplet></jmol>

File:Hc2711 nh3bh3 frequency.mol

2014-10-17T14:21:25Z

Hc2711:

Rep:Mod:imperial123

2014-10-17T14:20:52Z

Hc2711: /* NH3BH3 optimisation and frequency analysis */

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

freq

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

<pre>Low frequencies --- -798.6586 -401.9665 -401.6723 0.0011 0.0012 0.0014
Low frequencies --- 641.9215 642.0636 912.2909</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.096500 0.000450 NO
RMS Force 0.034759 0.000300 NO
Maximum Displacement 0.121535 0.001800 NO
RMS Displacement 0.061044 0.001200 NO </pre>

Rep:Mod:imperial123

2014-10-17T14:19:06Z

Hc2711:

questions
gabr3 frequency analysis

==EX3 section==

{| class="wikitable" border="1"
|+ table
! !! BH3 !! BBr3 !! GaBr3
|-
| r(E-X) || 1.19231|| 1.93395 || 2.35018
|-
| θ(X-E-X)|| 120.000 || 120.000 || 120.000
|}

==BH3 optimisation==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]
<pre> Item Value Threshold Converged?
Maximum Force 0.000220 0.000450 YES
RMS Force 0.000106 0.000300 YES
Maximum Displacement 0.000709 0.001800 YES
RMS Displacement 0.000447 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 optimisation.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711_BH3_OPT.LOG | here]]

==BH3 optimisation - 631g dp==

[[File:Hc2711 bh3 optimisation 631g dp real.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with 631g basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000012 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000061 0.001800 YES
RMS Displacement 0.000038 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 optimisation with 631g basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711 BH3 OPT 631g dp real.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 OPT 631G DP REAL.LOG | here]]

==GaBr3 optimisation==

[[File:Hc2711 GaBr3 pp optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule with LANL2DZ basis set.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000003 0.001800 YES
RMS Displacement 0.000002 0.001200 YES</pre>

<jmol><jmolApplet>
<title>GaBr3 optimisation with LANL2DZ basis sets</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 GaBr3 pp optimisation log.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking here: {{DOI|10042/31185}}

==BBr3 optimisation==

[[File:Hc2711 bbr3 opt after scan.png|thumb|A summary produced by Gaussian of an optimised B3LYP/6-31G(d,p)LANL2DZ BBr3]]
The optimisation file is linked to via clicking here: {{DOI|10042/31191}}

<pre> Item Value Threshold Converged?
Maximum Force 0.000015 0.000450 YES
RMS Force 0.000009 0.000300 YES
Maximum Displacement 0.000069 0.001800 YES
RMS Displacement 0.000041 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BBr3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bbr3 opt after scan.mol</uploadedFileContents>
</jmolApplet></jmol>

==BH3 frequency==
<pre>Low frequencies --- -0.9452 -0.8686 -0.0054 5.6959 11.6999 11.7380
Low frequencies --- 1162.9961 1213.1825 1213.1852</pre>

[[File:Hc2711 bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of a BH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000023 0.001800 YES
RMS Displacement 0.000012 0.001200 YES</pre>

<jmol><jmolApplet>
<title>BH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 bh3 frequency.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 BH3 FREQUENCY.LOG | here]]

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1163.00
|92.5483
|yes
|bend
|-
|1213.18
|14.0551
|slight
|bend
|-
|1213.19
|14.0587
|slight
|bend
|-
|2582.28
|0.0000
|no
|stretch
|-
|2715.45
|126.3301
|yes
|stretch
|-
|2715.45
|126.3206
|yes
|stretch
|}

[[File:Hc2711 bh3 frequency ir spectrum.png|An IR spectrum following frequency analysis of BH3 molecule.]]

==GaBr3 frequency analysis==
[[File:hc2711_bh3_optimisation.png|thumb|A summary produced by Gaussian of an optimised BH3 molecule.]]

<pre>Low frequencies --- -0.5252 -0.5247 -0.0024 -0.0010 0.0235 1.2010
Low frequencies --- 76.3744 76.3753 99.6982</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000000 0.000450 YES
RMS Force 0.000000 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000001 0.001200 YES</pre>

The frequency analysis file is linked to via clicking [[Media:Hc2711 gabr3 frequency.log | here]]

<jmol><jmolApplet>
<title>NH3 frequency</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 gabr3 frequency.mol2</uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|76.37
|3.3447
|no
|bend
|-
|76.38
|3.3447
|no
|bend
|-
|99.70
|9.2161
|slight
|bend
|-
|197.34
|0.0000
|no
|stretch
|-
|316.18
|57.0704
|yes
|stretch
|-
|316.19
|57.0746
|yes
|stretch
|}

[[File:Hc2711 gabr3 frequency ir spectrum.png]]

==BH3 molecular orbitals==

[[File:Hc2711 bh3 mo diagram.png|thumb|A molecular orbital diagram of BH3, showing Gaussian produced representations of the orbitals.]]

'''REFERENCE ^^^^^^^^^^^^^'''

==NH3 optimisation==
[[File:Hc2711 nh3 opt.png|thumb|A summary produced by Gaussian of an optimised NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000079 0.001800 YES
RMS Displacement 0.000053 0.001200 YES</pre>

<jmol><jmolApplet>
<title>NH3 optimisation</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>Hc2711 nh3 opt.mol</uploadedFileContents>
</jmolApplet></jmol>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 OPT.LOG | here]]

==NH3 frequency==
[[File:Hc2711 nh3 freq.png|thumb|A summary produced by Gaussian of a frequency analysis of an NH3 molecule.]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000007 0.000450 YES
RMS Force 0.000003 0.000300 YES
Maximum Displacement 0.000020 0.001800 YES
RMS Displacement 0.000009 0.001200 YES</pre>

<pre>Low frequencies --- -31.6862 -0.0021 -0.0019 -0.0010 13.0137 25.5415
Low frequencies --- 1089.5024 1694.1077 1694.1683</pre>

The optimisation file is linked to via clicking [[Media:HC2711 NH3 FREQUENCY.LOG | here]]

<jmol><jmolApplet>
<title>NH3 frequency analysis</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>HC2711_NH3_FREQUENCY.mol </uploadedFileContents>
</jmolApplet></jmol>

{| class="wikitable"
|+
|-
|wavenumber || Intensity || IR active? ||type
|-
|1089.50
|145.4472
|yes
|bend
|-
|1694.11
|13.5564
|slight
|bend
|-
|1694.17
|13.5568
|slight
|bend
|-
|3461.13
|1.0589
|no
|stretch
|-
|3589.59
|0.2701
|no
|stretch
|-
|3589.62
|0.2702
|no
|stretch
|}

[[File:Hc2711 nh3 frequency ir spectrum.png]]

==NBO analysis of NH3==

[[File:Hc2711 nh3 charge.png|thumb|A diagram visualising the charge distribution of an NH3 molecule.]]

[[File:Hc2711 nh3 nbo contribution charge.png|A diagram indicating the actual charge distribution per atom in the NH3 molecule.]]

==NH3BH3 optimisation and frequency analysis==

[[File:Hc2711 nh3bh3 frequency.png|thumb|A summary produced by Gaussian of a frequency analysis of an BH3NH3 molecule.]]

File:Hc2711 nh3bh3 frequency.png

2014-10-17T14:18:25Z

Hc2711: