Ev316

2018-05-17T19:09:51Z

Ev316:

dont forget
attempts to compare total energies for molecules computed using different methods/basis sets will loose marks!
does not report their energies to the right number of significant figures will loose marks!

comment on B-N dative bond

== BH<sub>3</sub> ==

===B3LYP/3-21G level===

[[File: BH3 optimisation 3-21.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000217 0.000450 YES
RMS Force 0.000105 0.000300 YES
Maximum Displacement 0.000692 0.001800 YES
RMS Displacement 0.000441 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT321.LOG| here]]

===B3LYP/6-31G level===

[[File: BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000203 0.000450 YES
RMS Force 0.000098 0.000300 YES
Maximum Displacement 0.000736 0.001800 YES
RMS Displacement 0.000394 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT2.LOG| here]]

B-H bond distance 1.19243
1.19264
1.19275
H-B-H bond angle 119.986

RMS gradient norm less than zero

===BH3 frequency analysis===

The frequency file is linked to [[Media:EV316_BH3_FREQ.LOG| here]]

<jmol>
<jmolApplet>
<title>BH3 B3LYP/3-21G level</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_BH3_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

<pre>Low frequencies --- -0.2263 -0.1037 -0.0055 47.9770 49.0378 49.0383
Low frequencies --- 1163.7209 1213.6704 1213.6731
</pre>

===IR spectrum===

[[File: IR_spectrum_BH3.png|800px]]

{| class="wikitable"
!Mode
!Frequency (cm<sup>-1</sup>
!Intensity
!Vibration Type
!IR active
|-
|1
|1163
|93
|Bend, out of plane
|Yes
|-
|2
|1213
|14
|Bend
|Yes
|-
|3
|1213
|14
|Bend
|Yes
|-
|4
|2582
|0
|Symmetric Stretch
|No
|-
|5
|2715
|126
|Asymmetric stretch
|Yes
|-
|6
|2715
|126
|Asymmetric stretch
|Yes
|-
|}

There are less than 6 peaks in the spectrum due to the degeneracy of some vibrations. The second and third, and also the fifth and sixth, vibrations are degenerate. Thus only two peaks are seen as opposed to four. The other vibrational mode that shows no peak is the symmetric stretch, as this gives no change in dipole moment and thus is not IR active it is not seen on the spectrum.

===MO analysis of BH<sub>3</sub>===

[[File:ev316 MO.png|left|600px|thumb|MO diagram taken from MO Theory by Patricia Hunt<ref>http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf</ref>.]]

Are there any significant differences between the real and LCAO MOs?

The LCAOs are ordered according to their energy but there is no quantitative analysis of energy as there is with the computed MOs. The real MOs are shown as with complete lobes as opposed to the fragmented LCAO MOs. The overall shape and structure seems to be a good match, yet the size of the lobes is somewhat larger for the real MOs.

What does this say about the accuracy and usefulness of qualitative MO theory?

Qualitative MO theory gives a good insight into the predicted bonding, shape and energy ordering of orbitals, yet does not provide the same level of information as the computed MOs. Qualitative MO theory remains a useful tool for analysis when computational methods are not possible or too expensive.

== NH<sub>3</sub> ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3 optimisation 6-31.png]]

The optimisation file is linked to [[Media:EV316_NH3_OPT.LOG| here]]

Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000004 0.000300 YES
Maximum Displacement 0.000012 0.001800 YES
RMS Displacement 0.000008 0.001200 YES

===Frequency===

[[File: NH3 frequency summary.png]]

The frequency file is linked to [[Media:EV316_NH3_FREQ.LOG| here]]

<pre>Low frequencies --- -8.5646 -8.5588 -0.0047 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865</pre>

<pre>Item Value Threshold Converged?
Maximum Force 0.000013 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000039 0.001800 YES
RMS Displacement 0.000013 0.001200 YES
</pre>

<jmol>
<jmolApplet>
<title>NH3 B3LYP/6-31G level</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_NH3_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

== NH<sub>3</sub>BH<sub>3</sub> analysis ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000513 0.001800 YES
RMS Displacement 0.000296 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_NH3BH3_FREQ.LOG| here]]

<pre>E(NH3)= -56.55777 a.u.
E(BH3)= -26.61532 a.u.
E(NH3BH3)= -83.22469 a.u.

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]
= -0.0516 a.u.
= -135 kJ/mol
</pre>

===Association energy===

The B-N dative bond is weak in comparison to many other covalent bonds.
It is in the same order of magnitude as other bond energies, and as such can be considered reasonable.

===Frequency===

[[File: NH3BH3 frequency summary.png]]

<pre> Low frequencies --- -12.2585 0.0011 0.0011 0.0012 19.3973 43.3115
Low frequencies --- 266.3451 632.1223 638.3345
</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000113 0.000450 YES
RMS Force 0.000059 0.000300 YES
Maximum Displacement 0.000701 0.001800 YES
RMS Displacement 0.000347 0.001200 YES
</pre>

The frequency file is linked to [[Media:EV316_NH3BH3_FREQ.LOG| here]]

<jmol>
<jmolApplet>
<title>Benzene B3LYP/6-31G level</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_NH3BH3_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

== BBr<sub>3</sub> analysis ==

Using B3LYP/GEN level

===Optimisation===

[[File: BBr3 optimisation GEN.png]]

The optimisation file is linked to [[Media:EV316_BBR3_OPT.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000018 0.000450 YES
RMS Force 0.000011 0.000300 YES
Maximum Displacement 0.000122 0.001800 YES
RMS Displacement 0.000075 0.001200 YES
</pre>

===Frequency===

[[File: BBr3 frequency GEN.png]]

The frequency file is linked to [[Media:EV316_BBR3_FREQ.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000145 0.001800 YES
RMS Displacement 0.000064 0.001200 YES
</pre>

<pre> Low frequencies --- -0.0002 -0.0001 0.0000 1.7959 3.5786 4.1660
Low frequencies --- 155.9323 156.0231 267.7073
</pre>

<jmol>
<jmolApplet>
<title>BBr3 B3LYP/GEN</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_BBR3_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

==Benzene==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 benzene optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000198 0.000450 YES
RMS Force 0.000082 0.000300 YES
Maximum Displacement 0.000849 0.001800 YES
RMS Displacement 0.000305 0.001200 YES

The optimisation file is linked to [[Media:EV316_BENZENE_OPT.LOG| here]]

=== Symmetry ===

D<sub>6h</sub> point group was imposed on benzene.

[[File: ev316 benzene sym optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000193 0.000450 YES
RMS Force 0.000079 0.000300 YES
Maximum Displacement 0.000830 0.001800 YES
RMS Displacement 0.000294 0.001200 YES

The symmetry file is linked to [[Media:EV316_BENZENE_SYM_OPT.LOG| here]]

===Frequency===

[[File: ev316 benzene frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000197 0.000450 YES
RMS Force 0.000085 0.000300 YES
Maximum Displacement 0.000780 0.001800 YES
RMS Displacement 0.000333 0.001200 YES
</pre>

<pre>Low frequencies --- -3.5606 -3.5606 -0.0088 -0.0044 -0.0042 10.0905
Low frequencies --- 413.9582 413.9582 621.1416</pre>

The frequency file is linked to [[Media:EV316_BENZENE_FREQ.LOG| here]]

<jmol>
<jmolApplet>
<title>Benzene B3LYP/6-31G level</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_BENZENE_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

==Borazine==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 borazine optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000021 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000142 0.001800 YES
RMS Displacement 0.000051 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BORAZINE_OPT.LOG| here]]

===Symmetry===

D<sub>3h</sub> point group was imposed on borazine.

[[File: ev316 borazine sym optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000072 0.001800 YES
RMS Displacement 0.000031 0.001200 YES
</pre>

===Frequency===

[[File: ev316 borazine frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000086 0.001800 YES
RMS Displacement 0.000033 0.001200 YES
</pre>

<pre>Low frequencies --- -9.6132 -9.3061 -9.0640 -0.0103 -0.0088 0.1106
Low frequencies --- 289.1848 289.1935 403.8445
</pre>

The frequency file is linked to [[Media:EV316_BORAZINE_FREQ.LOG| here]]

<jmol>
<jmolApplet>
<title>Borazine B3LYP/6-31G level</title><color>white</color>
<size>200</size><script>zoom 5;moveto 4 0 2 0 90 120;spin 2;</script>
<uploadedFileContents>EV316_BORAZINE_FREQ.LOG</uploadedFileContents>
</jmolApplet>
</jmol>

==Charge Analysis==

A colour range from -1.102 to 1.102 was used for the NBO charge analysis on both benzene and borazine.

The table below details the charge analysis for the two compounds:

<pre>
Molecule Charge on H Charge on ring atom

Benzene 0.239 -0.239 (C)

Borazine 0.432 (bonded to N) -1.102 (N)
-0.077 (bonded to B) 0.747 (B)
</pre>

Both molecules show polarity.

Carbon and nitrogen are more electronegative than hydrogen. Boron is more electropositive than hydrogen.

The image below shows the charge analysis for the two compounds:

[[File:ev316 benzene borazine charge analysis.png|left|600px|thumb|NBO charge analysis for: benzene on the top row and borazine on the bottom row. On the left, atoms are coloured by charge. On the right, they are shown with numerical charge values.]]

==MO Comparison==

Isoelectronic benzene and borazine. For both, core molecular orbitals are 1-6.

MO 21 is the HOMO.

MO 22 is the LUMO.

MO 20

MO 17

MO 9

{| class="wikitable"
!MO
!Benzene
!Borazine
!Comparison
|-
|9
|[[File: ev316 benzene MO9.png]]
|[[File: ev316 borazine MO9.png]]
|The benzene molecular orbital is symmetric out of phase. There is an equal contribution from each C-H bond, with a central nodal plane. The symmetry of the borazine molecular orbital is analogous to that seen in another molecule with the same D<sub>3h</sub> symmetry (3H e' fragment orbital in BH<sub3</sub> analysis). The benzene orbitals are symmetric, whereas the borazine is non-symmetric. There is no contribution from the Hs bonded to boron. There are two nodes.
There is one node which gives some antibonding character, however both molecular orbitals show a greater bonding character, making them bonding overall. The contribution is from s orbitals as we see there is not one phase 'on the other side'. Less contribution from BH.
Symmetric still in terms of having planes of symmetry, but not completely symmetrical due to differing phases. The borazine molecular orbital is less symmetrical.
|-
|17
|[[File: ev316 benzene MO17.png]]
|[[File: ev316 borazine MO17.png]]
|This is a bonding molecular orbital, with contributions from the p<sub>z</sub> orbitals on each C/B/N atom. The shape of the benzene molecular orbital is symmetric, whereas that of borazine is not. A smaller contribution from B is seen, due to it being more electropositive than N.
|-
|20
|[[File: ev316 benzene MO20.png]]
|[[File: ev316 borazine MO20.png]]
|p-orbital contributions
can see that the shape of the orbitals is similar, however the contribution from N is greater than that from B in the borazine molecule. In benzene, the orbitals have an equal contribution from all C. Overlap of in phase p<sub>z</sub> orbitals, with one central node. There is no contribution from 2 of the ring atoms in each complex. The through space out-of-phase interaction of the two
There are both antibonding and bonding character to this molecular orbital.
The through space antibonding character is a weaker interaction than the bonding orbital overlap, and thus the overall character is likely to be weakly bonding.
|}

==Aromaticity==

Both compounds are aromatic.
C (2.55)
Benzene is non-polar whereas borazine is polar due to the electronegativity difference between B (2.04) and N (3.04).

Aromaticity was originally attributed to the overlap of p<sub>z</sub> orbitals, yet this has since been determind inaccurate, as there are many notable exceptions to the rule.<ref>https://onlinelibrary.wiley.com/doi/epdf/10.1002/chem.200700250</ref>

==References==

Ev316

2018-05-17T15:34:17Z

2018-05-17T13:33:43Z

Ev316:

Ev316

2018-05-17T13:33:21Z

Ev316:

dont forget
attempts to compare total energies for molecules computed using different methods/basis sets will loose marks!
does not report their energies to the right number of significant figures will loose marks!

comment on B-N dative bond

== BH<sub>3</sub> ==

===B3LYP/3-21G level===

[[File: BH3 optimisation 3-21.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000217 0.000450 YES
RMS Force 0.000105 0.000300 YES
Maximum Displacement 0.000692 0.001800 YES
RMS Displacement 0.000441 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT321.LOG| here]]

===B3LYP/6-31G level===

[[File: BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000203 0.000450 YES
RMS Force 0.000098 0.000300 YES
Maximum Displacement 0.000736 0.001800 YES
RMS Displacement 0.000394 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT2.LOG| here]]

B-H bond distance 1.19243
1.19264
1.19275
H-B-H bond angle 119.986

RMS gradient norm less than zero

===BH3 frequency analysis===

The frequency file is linked to [[Media:EV316_BH3_FREQ.LOG| here]]

<pre>Low frequencies --- -0.2263 -0.1037 -0.0055 47.9770 49.0378 49.0383
Low frequencies --- 1163.7209 1213.6704 1213.6731
</pre>

less than 6 peaks in spectrum due to degeneracy of some peaks

[[File: IR_spectrum_BH3.png|800px]]

===MO analysis of BH<sub>3</sub>===

[[File:ev316.png|800px|thumb|MO diagram taken from MO Theory by Patricia Hunt<ref>http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf</ref>.]]

Are there any significant differences between the real and LCAO MOs?
What does this say about the accuracy and usefulness of qualitative MO theory?

== NH<sub>3</sub> ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3 optimisation 6-31.png]]

The optimisation file is linked to [[Media:EV316_NH3_OPT.LOG| here]]

Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000004 0.000300 YES
Maximum Displacement 0.000012 0.001800 YES
RMS Displacement 0.000008 0.001200 YES

===Frequency===

[[File: NH3 frequency summary.png]]

The frequency file is linked to [[Media:EV316_NH3_FREQ.LOG| here]]

<pre>Low frequencies --- -8.5646 -8.5588 -0.0047 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865</pre>

<pre>Item Value Threshold Converged?
Maximum Force 0.000013 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000039 0.001800 YES
RMS Displacement 0.000013 0.001200 YES
</pre>

== NH<sub>3</sub>BH<sub>3</sub> analysis ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000513 0.001800 YES
RMS Displacement 0.000296 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_NH3BH3_OPT.LOG| here]]

<pre>E(NH3)= -56.55777 a.u.
E(BH3)= -26.61532 a.u.
E(NH3BH3)= -83.22469 a.u.

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]
= -0.0516 a.u.
= -135.47581 kJ/mol
</pre>

===Association energy===

B-N dative bond weak

===Frequency===

[[File: NH3BH3 frequency summary.png]]

<pre> Low frequencies --- -12.2585 0.0011 0.0011 0.0012 19.3973 43.3115
Low frequencies --- 266.3451 632.1223 638.3345
</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000113 0.000450 YES
RMS Force 0.000059 0.000300 YES
Maximum Displacement 0.000701 0.001800 YES
RMS Displacement 0.000347 0.001200 YES
</pre>

The frequency file is linked to [[Media:EV316_NH3BH3_FREQ.LOG| here]]

== BBr<sub>3</sub> analysis ==

Using B3LYP/GEN level

===Optimisation===

[[File: BBr3 optimisation GEN.png]]

The optimisation file is linked to [[Media:EV316_BBR3_OPT.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000018 0.000450 YES
RMS Force 0.000011 0.000300 YES
Maximum Displacement 0.000122 0.001800 YES
RMS Displacement 0.000075 0.001200 YES
</pre>

===Frequency===

[[File: BBr3 frequency GEN.png]]

The frequency file is linked to [[Media:EV316_BBR3_FREQ.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000145 0.001800 YES
RMS Displacement 0.000064 0.001200 YES
</pre>

<pre> Low frequencies --- -0.0002 -0.0001 0.0000 1.7959 3.5786 4.1660
Low frequencies --- 155.9323 156.0231 267.7073
</pre>

==Benzene==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 benzene optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000198 0.000450 YES
RMS Force 0.000082 0.000300 YES
Maximum Displacement 0.000849 0.001800 YES
RMS Displacement 0.000305 0.001200 YES

The optimisation file is linked to [[Media:EV316_BENZENE_OPT.LOG| here]]

=== Symmetry ===

D<sub>6h</sub> point group was imposed on benzene.

[[File: ev316 benzene sym optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000193 0.000450 YES
RMS Force 0.000079 0.000300 YES
Maximum Displacement 0.000830 0.001800 YES
RMS Displacement 0.000294 0.001200 YES

The symmetry file is linked to [[Media:EV316_BENZENE_SYM_OPT.LOG| here]]

===Frequency===

[[File: ev316 benzene frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000197 0.000450 YES
RMS Force 0.000085 0.000300 YES
Maximum Displacement 0.000780 0.001800 YES
RMS Displacement 0.000333 0.001200 YES
</pre>

<pre>Low frequencies --- -3.5606 -3.5606 -0.0088 -0.0044 -0.0042 10.0905
Low frequencies --- 413.9582 413.9582 621.1416</pre>

The frequency file is linked to [[Media:EV316_BENZENE_FREQ.LOG| here]]

==Borazine==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 borazine optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000021 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000142 0.001800 YES
RMS Displacement 0.000051 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BORAZINE_OPT.LOG| here]]

===Symmetry===

D<sub>3h</sub> point group was imposed on borazine.

[[File: ev316 borazine sym optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000072 0.001800 YES
RMS Displacement 0.000031 0.001200 YES
</pre>

===Frequency===

[[File: ev316 borazine frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000086 0.001800 YES
RMS Displacement 0.000033 0.001200 YES
</pre>

<pre>Low frequencies --- -9.6132 -9.3061 -9.0640 -0.0103 -0.0088 0.1106
Low frequencies --- 289.1848 289.1935 403.8445
</pre>

The frequency file is linked to [[Media:EV316_BORAZINE_FREQ.LOG| here]]

==Charge Analysis==

A colour range from -1.102 to 1.102 was used for the NBO charge analysis on both benzene and borazine.

The image below shows the charge analysis for the two compounds.

[[File:ev316 benzene borazine charge analysis.png|800px|thumb|NBO charge analysis for: benzene on the top row and borazine on the bottom row. On the left, atoms are coloured by charge. On the right, they are shown with numerical charge values.]]

<pre>Molecule Charge on H Charge on ring atom
Benzene 0.239 -0.239
</pre>Borazine 0.432 (bonded to N) -1.102 (N)
-0.077 (bonded to B) 0.747 (B)
==Aromaticity==

==References==

Ev316

2018-05-17T13:02:54Z

Ev316: /* NH3BH3 analysis */

dont forget
attempts to compare total energies for molecules computed using different methods/basis sets will loose marks!
does not report their energies to the right number of significant figures will loose marks!

comment on B-N dative bond

== BH<sub>3</sub> ==

===B3LYP/3-21G level===

[[File: BH3 optimisation 3-21.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000217 0.000450 YES
RMS Force 0.000105 0.000300 YES
Maximum Displacement 0.000692 0.001800 YES
RMS Displacement 0.000441 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT321.LOG| here]]

===B3LYP/6-31G level===

[[File: BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000203 0.000450 YES
RMS Force 0.000098 0.000300 YES
Maximum Displacement 0.000736 0.001800 YES
RMS Displacement 0.000394 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BH3_OPT2.LOG| here]]

B-H bond distance 1.19243
1.19264
1.19275
H-B-H bond angle 119.986

RMS gradient norm less than zero

===BH3 frequency analysis===

The frequency file is linked to [[Media:EV316_BH3_FREQ.LOG| here]]

<pre>Low frequencies --- -0.2263 -0.1037 -0.0055 47.9770 49.0378 49.0383
Low frequencies --- 1163.7209 1213.6704 1213.6731
</pre>

less than 6 peaks in spectrum due to degeneracy of some peaks

[[File: IR_spectrum_BH3.png|800px]]

===MO analysis of BH<sub>3</sub>===

[[File:ev316.png|800px|thumb|MO diagram taken from MO Theory by Patricia Hunt<ref>http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf</ref>.]]

Are there any significant differences between the real and LCAO MOs?
What does this say about the accuracy and usefulness of qualitative MO theory?

== NH<sub>3</sub> ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3 optimisation 6-31.png]]

The optimisation file is linked to [[Media:EV316_NH3_OPT.LOG| here]]

Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000004 0.000300 YES
Maximum Displacement 0.000012 0.001800 YES
RMS Displacement 0.000008 0.001200 YES

===Frequency===

[[File: NH3 frequency summary.png]]

The frequency file is linked to [[Media:EV316_NH3_FREQ.LOG| here]]

<pre>Low frequencies --- -8.5646 -8.5588 -0.0047 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865</pre>

<pre>Item Value Threshold Converged?
Maximum Force 0.000013 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000039 0.001800 YES
RMS Displacement 0.000013 0.001200 YES
</pre>

== NH<sub>3</sub>BH<sub>3</sub> analysis ==

Using B3LYP/6-31G level

===Optimisation===

[[File: NH3BH3 optimisation 6-31.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000513 0.001800 YES
RMS Displacement 0.000296 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_NH3BH3_OPT.LOG| here]]

<pre>E(NH3)= -56.55777 a.u.
E(BH3)= -26.61532 a.u.
E(NH3BH3)= -83.22469 a.u.

ΔE=E(NH3BH3)-[E(NH3)+E(BH3)]
= -0.0516 a.u.
= -135.47581 kJ/mol
</pre>

===Association energy===

B-N dative bond weak

===Frequency===

[[File: NH3BH3 frequency summary.png]]

<pre> Low frequencies --- -12.2585 0.0011 0.0011 0.0012 19.3973 43.3115
Low frequencies --- 266.3451 632.1223 638.3345
</pre>

<pre> Item Value Threshold Converged?
Maximum Force 0.000113 0.000450 YES
RMS Force 0.000059 0.000300 YES
Maximum Displacement 0.000701 0.001800 YES
RMS Displacement 0.000347 0.001200 YES
</pre>

The frequency file is linked to [[Media:EV316_NH3BH3_FREQ.LOG| here]]

== BBr<sub>3</sub> analysis ==

Using B3LYP/GEN level

===Optimisation===

[[File: BBr3 optimisation GEN.png]]

The optimisation file is linked to [[Media:EV316_BBR3_OPT.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000018 0.000450 YES
RMS Force 0.000011 0.000300 YES
Maximum Displacement 0.000122 0.001800 YES
RMS Displacement 0.000075 0.001200 YES
</pre>

===Frequency===

[[File: BBr3 frequency GEN.png]]

The frequency file is linked to [[Media:EV316_BBR3_FREQ.LOG| here]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000145 0.001800 YES
RMS Displacement 0.000064 0.001200 YES
</pre>

<pre> Low frequencies --- -0.0002 -0.0001 0.0000 1.7959 3.5786 4.1660
Low frequencies --- 155.9323 156.0231 267.7073
</pre>

==Benzene==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 benzene optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000198 0.000450 YES
RMS Force 0.000082 0.000300 YES
Maximum Displacement 0.000849 0.001800 YES
RMS Displacement 0.000305 0.001200 YES

The optimisation file is linked to [[Media:EV316_BENZENE_OPT.LOG| here]]

=== Symmetry ===

D<sub>6h</sub> point group was imposed on benzene.

[[File: ev316 benzene sym optimisation summary.png]]

Item Value Threshold Converged?
Maximum Force 0.000193 0.000450 YES
RMS Force 0.000079 0.000300 YES
Maximum Displacement 0.000830 0.001800 YES
RMS Displacement 0.000294 0.001200 YES

The symmetry file is linked to [[Media:EV316_BENZENE_SYM_OPT.LOG| here]]

===Frequency===

[[File: ev316 benzene frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000197 0.000450 YES
RMS Force 0.000085 0.000300 YES
Maximum Displacement 0.000780 0.001800 YES
RMS Displacement 0.000333 0.001200 YES
</pre>

<pre>Low frequencies --- -3.5606 -3.5606 -0.0088 -0.0044 -0.0042 10.0905
Low frequencies --- 413.9582 413.9582 621.1416</pre>

The frequency file is linked to [[Media:EV316_BENZENE_FREQ.LOG| here]]

==Borazine==

Using B3LYP/6-31G level

===Optimisation===

[[File: ev316 borazine optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000021 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000142 0.001800 YES
RMS Displacement 0.000051 0.001200 YES
</pre>

The optimisation file is linked to [[Media:EV316_BORAZINE_OPT.LOG| here]]

===Symmetry===

D<sub>3h</sub> point group was imposed on borazine.

[[File: ev316 borazine sym optimisation summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000024 0.000450 YES
RMS Force 0.000008 0.000300 YES
Maximum Displacement 0.000072 0.001800 YES
RMS Displacement 0.000031 0.001200 YES
</pre>

===Frequency===

[[File: ev316 borazine frequency summary.png]]

<pre> Item Value Threshold Converged?
Maximum Force 0.000019 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000086 0.001800 YES
RMS Displacement 0.000033 0.001200 YES
</pre>

<pre>Low frequencies --- -9.6132 -9.3061 -9.0640 -0.0103 -0.0088 0.1106
Low frequencies --- 289.1848 289.1935 403.8445
</pre>

The frequency file is linked to [[Media:EV316_BORAZINE_FREQ.LOG| here]]

==Aromaticity==

==References==