2019-05-17T16:20:37Z

Av4217: /* Molecular Orbitals */

==Day 1: Revision==
===BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3_summary_av4217.png]]
<pre>

Item Value Threshold Converged?
Maximum Force 0.000011 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000042 0.001800 YES
RMS Displacement 0.000027 0.001200 YES
Predicted change in Energy=-6.625456D-10
Optimization completed.
-- Stationary point found.
</pre>
[[File:BH3_FREQ_AV4217.LOG]]
<pre>
Low frequencies --- -7.5936 -1.5614 -0.0055 0.6514 6.9319 7.1055
Low frequencies --- 1162.9677 1213.1634 1213.1661
</pre>
<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>
{| class="wikitable" border="1"
|+ Vibrations
! Frequency/cm-1 !! Intensity/a.u !! Symmetry !!IR Active? !! Type
|-
| 1162 || 92 ||A2 ||Yes || Bend
|-
| 1213 || 14 || E'||Weak || Bend
|-
| 1213 || 14 || E' ||Weak || Bend
|-
| 2582 || 0|| A'1||No || Symmetric Stretch
|-
| 2715 || 126 ||E'||Yes || Asymmetric Stretch
|-
| 2715 || 126||E' ||Yes || Asymmetric Stretch
|}

[[File:BH3_spectrum_av4217.png]]

There are only 3 peaks when there are 6 vibration frequencies shown. This is because two pairs of vibrations (1213 cm-1 and 2715 cm-1) are degenerate, they have the same frequency, so only one peak is seen for each. Hence, two peaks are not seen in the spectrum. The frequency at 2582 cm-1 has 0 intensity as it's not IR active, so this peak is also not seen.

[[File:BH3_MO_av42171.png|1000px|thumb|center|Molecular Orbital Diagram of BH3. Molecular Orbital Diagram taken from Professor Hunt's course.<ref name="MO" />]]

The LCAO MOs shows the two separate atomic orbitals which combine to form the molecular orbitals, while the real MOs show what the molecular orbital look like when the orbitals combined. The LCAO MOs don't show what the final molecular orbital looks like when the electron density is shared. The LCAO MOs are useful since, they show the individual atomic orbitals that form the molecular orbital. Also, they can be used to predict whether the final orbital is bonding, antibonding or non-bonding and their relative energies. However, they're not accurate in predicting the distribution of electron density in the molecular orbital, especially antibonding orbitals.

===NH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:NH3_summary_av4217.png]]

<pre>
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
Predicted change in Energy=-9.844605D-11
Optimization completed.
-- Stationary point found.
</pre>

[[File:NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -8.5646 -8.5588 -0.0044 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865
</pre>

<jmol><jmolApplet>
<title>Ammonia Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NH3 OPT 6DP AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>

===NH3BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3NH3_summary1_av4217.png]]
<pre>
Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000540 0.001800 YES
RMS Displacement 0.000297 0.001200 YES
Predicted change in Energy=-1.663823D-07
Optimization completed.
-- Stationary point found.

</pre>

[[File:BH3NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0014 -0.0010 -0.0010 12.5258 18.8909 42.6127
Low frequencies --- 266.2536 632.2667 638.9708
</pre>

<jmol><jmolApplet>
<title>BH3NH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Bond Energy===
E(NH3)=-26.61532 Hartrees

E(BH3)=-56.55777 Hartrees

E(NH3BH3)=-83.22468 Hartrees

-83.22468 + 26.61532 + 56.55777 = -0.05159 Hartrees

-135.5 kJmol-1

This is a relatively weak bond compare to other covalent bonds, such as a H-H bond which is around 435 kJmol-1.

==Day 1: New==
===NI3===
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:NI3_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000102 0.000450 YES
RMS Force 0.000075 0.000300 YES
Maximum Displacement 0.000667 0.001800 YES
RMS Displacement 0.000490 0.001200 YES
Predicted change in Energy=-9.239334D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:NI3_1FREQ_6DP_AV4217.LOG]]

<pre>
Low frequencies --- -12.3847 -12.3783 -5.6131 -0.0040 0.0194 0.0711
Low frequencies --- 100.9307 100.9314 147.2333
</pre>

<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NI3_1OPT_6DP_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The optimal bond distance of N-I is 2.184 a.u

==Day 2 and 3: Lewis Acids and Bases==
[[File:Al2Br2Cl4 av4217.png]]

===2 Bridging Br ions===
[[File:Bridging_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Bridging_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000003 0.000450 YES
RMS Force 0.000001 0.000300 YES
Maximum Displacement 0.000040 0.001800 YES
RMS Displacement 0.000015 0.001200 YES
Predicted change in Energy=-2.937162D-10
Optimization completed.
-- Stationary point found.
</pre>

[[File:BR_BRIDGING_FREQ1_AV4217.LOG]]

<pre>
Low frequencies --- -5.2784 -5.2119 -3.0962 0.0043 0.0044 0.0049
Low frequencies --- 14.7649 63.2302 86.0517
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BR_BRIDGING_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

Energy of isomer = -2352.40631 Hartrees = -6176243.2 kJ/mol

===Trans terminal Br ions===
[[File:Trans_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Trans_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000029 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000211 0.001800 YES
RMS Displacement 0.000080 0.001200 YES
Predicted change in Energy=-1.286645D-08
Optimization completed.
-- Stationary point found.
</pre>
[[File:TRANS_BR_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -4.0892 -2.4307 0.0033 0.0037 0.0038 0.9105
Low frequencies --- 17.7328 48.9885 72.9546
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>TRANS_BR_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The energy of the isomer = -2352.41629 Hartrees = -6176269.4 kJ/mol

====Relative Energies====

ΔE = -2352.412629 - -2352.40631 = 0.006319 Hartrees = 16.6 kJ/mol

The isomer with chlorine as the bridging atom has a slightly lower energy indicating the isomer is more stable. This could be due to the chlorine being the bridging atom as it is in the same period as aluminium. Therefore, there is a larger orbital overlap and electron density isn't as diffuse as with bromine atoms. The electron density is shared better over the 3 centres and the bonds are shorter. Meaning the bond is stronger and the isomer is more stable.

=== AlCl2Br Molecule===
'''B3LYP/6-31G(d.p)LANL2DZ level'''

[[File:Monomer_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000136 0.000450 YES
RMS Force 0.000073 0.000300 YES
Maximum Displacement 0.000681 0.001800 YES
RMS Displacement 0.000497 0.001200 YES
Predicted change in Energy=-7.984447D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:MONOMER1_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0033 -0.0015 0.0032 1.3569 3.6367 4.2604
Low frequencies --- 120.5042 133.9178 185.8950
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>MONOMER1_FREQ_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

====Dissociation Energy====
E(AlCl2Br) = -1176.19014 Hartrees

E(Al2Cl4Br2) = -2352.41629 Hartrees

Dissociation Energy = 2(-1176.19014) - -2352.41629 = 0.03601 Hartrees = 94.5 kJ/mol

The reaction is endothermic suggesting the dimer is more stable, as its at a lower energy.

===Molecular Orbitals===
Real MOs and LCAOs of three molecular orbitals of the trans isomer (lowest energy)

[[File:Bonding_MO_av4217.png|left]]

[[File:Abonding_av4217.png|left]]

[[File:Sbonding_av4217.png|left]]

==References==

<references>
<ref name="MO">http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf - accessed 17/05/2019</ref>
</references>

File:Abonding av4217.png

2019-05-17T16:20:22Z

Av4217:

Inorganic:av4217

2019-05-17T16:18:33Z

Av4217: /* Molecular Orbitals */

==Day 1: Revision==
===BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3_summary_av4217.png]]
<pre>

Item Value Threshold Converged?
Maximum Force 0.000011 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000042 0.001800 YES
RMS Displacement 0.000027 0.001200 YES
Predicted change in Energy=-6.625456D-10
Optimization completed.
-- Stationary point found.
</pre>
[[File:BH3_FREQ_AV4217.LOG]]
<pre>
Low frequencies --- -7.5936 -1.5614 -0.0055 0.6514 6.9319 7.1055
Low frequencies --- 1162.9677 1213.1634 1213.1661
</pre>
<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>
{| class="wikitable" border="1"
|+ Vibrations
! Frequency/cm-1 !! Intensity/a.u !! Symmetry !!IR Active? !! Type
|-
| 1162 || 92 ||A2 ||Yes || Bend
|-
| 1213 || 14 || E'||Weak || Bend
|-
| 1213 || 14 || E' ||Weak || Bend
|-
| 2582 || 0|| A'1||No || Symmetric Stretch
|-
| 2715 || 126 ||E'||Yes || Asymmetric Stretch
|-
| 2715 || 126||E' ||Yes || Asymmetric Stretch
|}

[[File:BH3_spectrum_av4217.png]]

There are only 3 peaks when there are 6 vibration frequencies shown. This is because two pairs of vibrations (1213 cm-1 and 2715 cm-1) are degenerate, they have the same frequency, so only one peak is seen for each. Hence, two peaks are not seen in the spectrum. The frequency at 2582 cm-1 has 0 intensity as it's not IR active, so this peak is also not seen.

[[File:BH3_MO_av42171.png|1000px|thumb|center|Molecular Orbital Diagram of BH3. Molecular Orbital Diagram taken from Professor Hunt's course.<ref name="MO" />]]

The LCAO MOs shows the two separate atomic orbitals which combine to form the molecular orbitals, while the real MOs show what the molecular orbital look like when the orbitals combined. The LCAO MOs don't show what the final molecular orbital looks like when the electron density is shared. The LCAO MOs are useful since, they show the individual atomic orbitals that form the molecular orbital. Also, they can be used to predict whether the final orbital is bonding, antibonding or non-bonding and their relative energies. However, they're not accurate in predicting the distribution of electron density in the molecular orbital, especially antibonding orbitals.

===NH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:NH3_summary_av4217.png]]

<pre>
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
Predicted change in Energy=-9.844605D-11
Optimization completed.
-- Stationary point found.
</pre>

[[File:NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -8.5646 -8.5588 -0.0044 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865
</pre>

<jmol><jmolApplet>
<title>Ammonia Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NH3 OPT 6DP AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>

===NH3BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3NH3_summary1_av4217.png]]
<pre>
Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000540 0.001800 YES
RMS Displacement 0.000297 0.001200 YES
Predicted change in Energy=-1.663823D-07
Optimization completed.
-- Stationary point found.

</pre>

[[File:BH3NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0014 -0.0010 -0.0010 12.5258 18.8909 42.6127
Low frequencies --- 266.2536 632.2667 638.9708
</pre>

<jmol><jmolApplet>
<title>BH3NH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Bond Energy===
E(NH3)=-26.61532 Hartrees

E(BH3)=-56.55777 Hartrees

E(NH3BH3)=-83.22468 Hartrees

-83.22468 + 26.61532 + 56.55777 = -0.05159 Hartrees

-135.5 kJmol-1

This is a relatively weak bond compare to other covalent bonds, such as a H-H bond which is around 435 kJmol-1.

==Day 1: New==
===NI3===
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:NI3_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000102 0.000450 YES
RMS Force 0.000075 0.000300 YES
Maximum Displacement 0.000667 0.001800 YES
RMS Displacement 0.000490 0.001200 YES
Predicted change in Energy=-9.239334D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:NI3_1FREQ_6DP_AV4217.LOG]]

<pre>
Low frequencies --- -12.3847 -12.3783 -5.6131 -0.0040 0.0194 0.0711
Low frequencies --- 100.9307 100.9314 147.2333
</pre>

<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NI3_1OPT_6DP_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The optimal bond distance of N-I is 2.184 a.u

==Day 2 and 3: Lewis Acids and Bases==
[[File:Al2Br2Cl4 av4217.png]]

===2 Bridging Br ions===
[[File:Bridging_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Bridging_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000003 0.000450 YES
RMS Force 0.000001 0.000300 YES
Maximum Displacement 0.000040 0.001800 YES
RMS Displacement 0.000015 0.001200 YES
Predicted change in Energy=-2.937162D-10
Optimization completed.
-- Stationary point found.
</pre>

[[File:BR_BRIDGING_FREQ1_AV4217.LOG]]

<pre>
Low frequencies --- -5.2784 -5.2119 -3.0962 0.0043 0.0044 0.0049
Low frequencies --- 14.7649 63.2302 86.0517
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BR_BRIDGING_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

Energy of isomer = -2352.40631 Hartrees = -6176243.2 kJ/mol

===Trans terminal Br ions===
[[File:Trans_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Trans_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000029 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000211 0.001800 YES
RMS Displacement 0.000080 0.001200 YES
Predicted change in Energy=-1.286645D-08
Optimization completed.
-- Stationary point found.
</pre>
[[File:TRANS_BR_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -4.0892 -2.4307 0.0033 0.0037 0.0038 0.9105
Low frequencies --- 17.7328 48.9885 72.9546
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>TRANS_BR_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The energy of the isomer = -2352.41629 Hartrees = -6176269.4 kJ/mol

====Relative Energies====

ΔE = -2352.412629 - -2352.40631 = 0.006319 Hartrees = 16.6 kJ/mol

The isomer with chlorine as the bridging atom has a slightly lower energy indicating the isomer is more stable. This could be due to the chlorine being the bridging atom as it is in the same period as aluminium. Therefore, there is a larger orbital overlap and electron density isn't as diffuse as with bromine atoms. The electron density is shared better over the 3 centres and the bonds are shorter. Meaning the bond is stronger and the isomer is more stable.

=== AlCl2Br Molecule===
'''B3LYP/6-31G(d.p)LANL2DZ level'''

[[File:Monomer_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000136 0.000450 YES
RMS Force 0.000073 0.000300 YES
Maximum Displacement 0.000681 0.001800 YES
RMS Displacement 0.000497 0.001200 YES
Predicted change in Energy=-7.984447D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:MONOMER1_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0033 -0.0015 0.0032 1.3569 3.6367 4.2604
Low frequencies --- 120.5042 133.9178 185.8950
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>MONOMER1_FREQ_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

====Dissociation Energy====
E(AlCl2Br) = -1176.19014 Hartrees

E(Al2Cl4Br2) = -2352.41629 Hartrees

Dissociation Energy = 2(-1176.19014) - -2352.41629 = 0.03601 Hartrees = 94.5 kJ/mol

The reaction is endothermic suggesting the dimer is more stable, as its at a lower energy.

===Molecular Orbitals===
Real MOs and LCAOs of three molecular orbitals of the trans isomer (lowest energy)

[[File:Bonding_MO_av4217.png|left]]

[[File:Antibonding_MO_av4217.png|left]]

[[File:Sbonding_av4217.png|left]]

==References==

<references>
<ref name="MO">http://www.huntresearchgroup.org.uk/teaching/teaching_comp_lab_year2a/Tut_MO_diagram_BH3.pdf - accessed 17/05/2019</ref>
</references>

2019-05-17T15:37:23Z

Av4217: /* Molecular Orbitals */

==Day 1: Revision==
===BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3_summary_av4217.png]]
<pre>

Item Value Threshold Converged?
Maximum Force 0.000011 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000042 0.001800 YES
RMS Displacement 0.000027 0.001200 YES
Predicted change in Energy=-6.625456D-10
Optimization completed.
-- Stationary point found.
</pre>
[[File:BH3_FREQ_AV4217.LOG]]
<pre>
Low frequencies --- -7.5936 -1.5614 -0.0055 0.6514 6.9319 7.1055
Low frequencies --- 1162.9677 1213.1634 1213.1661
</pre>
<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>
{| class="wikitable" border="1"
|+ Vibrations
! Frequency/cm-1 !! Intensity/a.u !! Symmetry !!IR Active? !! Type
|-
| 1162 || 92 ||A2 ||Yes || Bend
|-
| 1213 || 14 || E'||Weak || Bend
|-
| 1213 || 14 || E' ||Weak || Bend
|-
| 2582 || 0|| A'1||No || Symmetric Stretch
|-
| 2715 || 126 ||E'||Yes || Asymmetric Stretch
|-
| 2715 || 126||E' ||Yes || Asymmetric Stretch
|}

[[File:BH3_spectrum_av4217.png]]

There are only 3 peaks when there are 6 vibration frequencies shown. This is because two pairs of vibrations (1213 cm-1 and 2715 cm-1) are degenerate, they have the same frequency, so only one peak is seen for each. Hence, two peaks are not seen in the spectrum. The frequency at 2582 cm-1 has 0 intensity as it's not IR active, so this peak is also not seen.

[[File:BH3_MO_av42171.png]]

The LCAO MOs shows the two separate atomic orbitals which combine to form the molecular orbitals, while the real MOs show what the molecular orbital look like when the orbitals combined. The LCAO MOs don't show what the final molecular orbital looks like when the electron density is shared. The LCAO MOs are useful since, they show the individual atomic orbitals that form the molecular orbital. Also, they can be used to predict whether the final orbital is bonding, antibonding or non-bonding and their relative energies. However, they're not accurate in predicting the distribution of electron density in the molecular orbital, especially antibonding orbitals.

===NH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:NH3_summary_av4217.png]]

<pre>
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
Predicted change in Energy=-9.844605D-11
Optimization completed.
-- Stationary point found.
</pre>

[[File:NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -8.5646 -8.5588 -0.0044 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865
</pre>

<jmol><jmolApplet>
<title>Ammonia Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NH3 OPT 6DP AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>

===NH3BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3NH3_summary1_av4217.png]]
<pre>
Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000540 0.001800 YES
RMS Displacement 0.000297 0.001200 YES
Predicted change in Energy=-1.663823D-07
Optimization completed.
-- Stationary point found.

</pre>

[[File:BH3NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0014 -0.0010 -0.0010 12.5258 18.8909 42.6127
Low frequencies --- 266.2536 632.2667 638.9708
</pre>

<jmol><jmolApplet>
<title>BH3NH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Bond Energy===
E(NH3)=-26.61532 Hartrees

E(BH3)=-56.55777 Hartrees

E(NH3BH3)=-83.22468 Hartrees

-83.22468 + 26.61532 + 56.55777 = -0.05159 Hartrees

-135.5 kJmol-1

This is a relatively weak bond compare to other covalent bonds, such as a H-H bond which is around 435 kJmol-1.

==Day 1: New==
===NI3===
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:NI3_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000102 0.000450 YES
RMS Force 0.000075 0.000300 YES
Maximum Displacement 0.000667 0.001800 YES
RMS Displacement 0.000490 0.001200 YES
Predicted change in Energy=-9.239334D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:NI3_1FREQ_6DP_AV4217.LOG]]

<pre>
Low frequencies --- -12.3847 -12.3783 -5.6131 -0.0040 0.0194 0.0711
Low frequencies --- 100.9307 100.9314 147.2333
</pre>

<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NI3_1OPT_6DP_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The optimal bond distance of N-I is 2.184 a.u

==Day 2 and 3: Lewis Acids and Bases==
[[File:Al2Br2Cl4 av4217.png]]

===2 Bridging Br ions===
[[File:Bridging_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Bridging_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000003 0.000450 YES
RMS Force 0.000001 0.000300 YES
Maximum Displacement 0.000040 0.001800 YES
RMS Displacement 0.000015 0.001200 YES
Predicted change in Energy=-2.937162D-10
Optimization completed.
-- Stationary point found.
</pre>

[[File:BR_BRIDGING_FREQ1_AV4217.LOG]]

<pre>
Low frequencies --- -5.2784 -5.2119 -3.0962 0.0043 0.0044 0.0049
Low frequencies --- 14.7649 63.2302 86.0517
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BR_BRIDGING_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

Energy of isomer = -2352.40631 Hartrees = -6176243.2 kJ/mol

===Trans terminal Br ions===
[[File:Trans_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Trans_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000029 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000211 0.001800 YES
RMS Displacement 0.000080 0.001200 YES
Predicted change in Energy=-1.286645D-08
Optimization completed.
-- Stationary point found.
</pre>
[[File:TRANS_BR_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -4.0892 -2.4307 0.0033 0.0037 0.0038 0.9105
Low frequencies --- 17.7328 48.9885 72.9546
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>TRANS_BR_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The energy of the isomer = -2352.41629 Hartrees = -6176269.4 kJ/mol

====Relative Energies====

ΔE = -2352.412629 - -2352.40631 = 0.006319 Hartrees = 16.6 kJ/mol

The isomer with chlorine as the bridging atom has a slightly lower energy indicating the isomer is more stable. This could be due to the chlorine being the bridging atom as it is in the same period as aluminium. Therefore, there is a larger orbital overlap and electron density isn't as diffuse as with bromine atoms. The electron density is shared better over the 3 centres and the bonds are shorter. Meaning the bond is stronger and the isomer is more stable.

=== AlCl2Br Molecule===
'''B3LYP/6-31G(d.p)LANL2DZ level'''

[[File:Monomer_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000136 0.000450 YES
RMS Force 0.000073 0.000300 YES
Maximum Displacement 0.000681 0.001800 YES
RMS Displacement 0.000497 0.001200 YES
Predicted change in Energy=-7.984447D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:MONOMER1_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0033 -0.0015 0.0032 1.3569 3.6367 4.2604
Low frequencies --- 120.5042 133.9178 185.8950
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>MONOMER1_FREQ_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

====Dissociation Energy====
E(AlCl2Br) = -1176.19014 Hartrees

E(Al2Cl4Br2) = -2352.41629 Hartrees

Dissociation Energy = 2(-1176.19014) - -2352.41629 = 0.03601 Hartrees = 94.5 kJ/mol

The reaction is endothermic suggesting the dimer is more stable, as its at a lower energy.

===Molecular Orbitals===
Real MOs and LCAOs of three molecular orbitals of the trans isomer (lowest energy)
[[File:Bonding_MO_av4217.png|left]]
[[File:Antibonding_MO_av4217.png|left]]
[[File:S_bonding_MO_av4217.png|left]]

File:S bonding MO av4217.png

2019-05-17T15:37:05Z

Av4217:

File:Antibonding MO av4217.png

2019-05-17T15:36:41Z

Av4217:

2019-05-17T13:05:42Z

Av4217: /* AlCl2Br Molecule */

==Day 1: Revision==
===BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3_summary_av4217.png]]
<pre>

Item Value Threshold Converged?
Maximum Force 0.000011 0.000450 YES
RMS Force 0.000007 0.000300 YES
Maximum Displacement 0.000042 0.001800 YES
RMS Displacement 0.000027 0.001200 YES
Predicted change in Energy=-6.625456D-10
Optimization completed.
-- Stationary point found.
</pre>
[[File:BH3_FREQ_AV4217.LOG]]
<pre>
Low frequencies --- -7.5936 -1.5614 -0.0055 0.6514 6.9319 7.1055
Low frequencies --- 1162.9677 1213.1634 1213.1661
</pre>
<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>
{| class="wikitable" border="1"
|+ Vibrations
! Frequency/cm-1 !! Intensity/a.u !! Symmetry !!IR Active? !! Type
|-
| 1162 || 92 ||A2 ||Yes || Bend
|-
| 1213 || 14 || E'||Weak || Bend
|-
| 1213 || 14 || E' ||Weak || Bend
|-
| 2582 || 0|| A'1||No || Symmetric Stretch
|-
| 2715 || 126 ||E'||Yes || Asymmetric Stretch
|-
| 2715 || 126||E' ||Yes || Asymmetric Stretch
|}

[[File:BH3_spectrum_av4217.png]]

There are only 3 peaks when there are 6 vibration frequencies shown. This is because two pairs of vibrations (1213 cm-1 and 2715 cm-1) are degenerate, they have the same frequency, so only one peak is seen for each. Hence, two peaks are not seen in the spectrum. The frequency at 2582 cm-1 has 0 intensity as it's not IR active, so this peak is also not seen.

[[File:BH3_MO_av42171.png]]

The LCAO MOs shows the two separate atomic orbitals which combine to form the molecular orbitals, while the real MOs show what the molecular orbital look like when the orbitals combined. The LCAO MOs don't show what the final molecular orbital looks like when the electron density is shared. The LCAO MOs are useful since, they show the individual atomic orbitals that form the molecular orbital. Also, they can be used to predict whether the final orbital is bonding, antibonding or non-bonding and their relative energies. However, they're not accurate in predicting the distribution of electron density in the molecular orbital.

===NH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:NH3_summary_av4217.png]]

<pre>
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
Predicted change in Energy=-9.844605D-11
Optimization completed.
-- Stationary point found.
</pre>

[[File:NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -8.5646 -8.5588 -0.0044 0.0454 0.1784 26.4183
Low frequencies --- 1089.7603 1694.1865 1694.1865
</pre>

<jmol><jmolApplet>
<title>Ammonia Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NH3 OPT 6DP AV4217.LOG </uploadedFileContents>
</jmolApplet></jmol>

===NH3BH3 Molecule===
'''B3LYP/6-31G(d.p) level'''
[[File:BH3NH3_summary1_av4217.png]]
<pre>
Item Value Threshold Converged?
Maximum Force 0.000122 0.000450 YES
RMS Force 0.000058 0.000300 YES
Maximum Displacement 0.000540 0.001800 YES
RMS Displacement 0.000297 0.001200 YES
Predicted change in Energy=-1.663823D-07
Optimization completed.
-- Stationary point found.

</pre>

[[File:BH3NH3_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0014 -0.0010 -0.0010 12.5258 18.8909 42.6127
Low frequencies --- 266.2536 632.2667 638.9708
</pre>

<jmol><jmolApplet>
<title>BH3NH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BH3_SYM1_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Bond Energy===
E(NH3)=-26.61532 Hartrees

E(BH3)=-56.55777 Hartrees

E(NH3BH3)=-83.22468 Hartrees

-83.22468 + 26.61532 + 56.55777 = -0.05159 Hartrees

-135.5 kJmol-1

This is a relatively weak bond compare to other covalent bonds, such as a H-H bond which is around 435 kJmol-1.

==Day 1: New==
===NI3===
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:NI3_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000102 0.000450 YES
RMS Force 0.000075 0.000300 YES
Maximum Displacement 0.000667 0.001800 YES
RMS Displacement 0.000490 0.001200 YES
Predicted change in Energy=-9.239334D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:NI3_1FREQ_6DP_AV4217.LOG]]

<pre>
Low frequencies --- -12.3847 -12.3783 -5.6131 -0.0040 0.0194 0.0711
Low frequencies --- 100.9307 100.9314 147.2333
</pre>

<jmol><jmolApplet>
<title>BH3 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>NI3_1OPT_6DP_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The optimal bond distance of N-I is 2.184 a.u

==Day 2 and 3: Lewis Acids and Bases==
[[File:Al2Br2Cl4 av4217.png]]

===2 Bridging Br ions===
[[File:Bridging_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Bridging_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000003 0.000450 YES
RMS Force 0.000001 0.000300 YES
Maximum Displacement 0.000040 0.001800 YES
RMS Displacement 0.000015 0.001200 YES
Predicted change in Energy=-2.937162D-10
Optimization completed.
-- Stationary point found.
</pre>

[[File:BR_BRIDGING_FREQ1_AV4217.LOG]]

<pre>
Low frequencies --- -5.2784 -5.2119 -3.0962 0.0043 0.0044 0.0049
Low frequencies --- 14.7649 63.2302 86.0517
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>BR_BRIDGING_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

Energy of isomer = -2352.40631 Hartrees = -6176243.2 kJ/mol

===Trans terminal Br ions===
[[File:Trans_Br_av4217.png]]
'''B3LYP/6-31G(d.p)LANL2DZ level'''
[[File:Trans_Br_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000029 0.000450 YES
RMS Force 0.000012 0.000300 YES
Maximum Displacement 0.000211 0.001800 YES
RMS Displacement 0.000080 0.001200 YES
Predicted change in Energy=-1.286645D-08
Optimization completed.
-- Stationary point found.
</pre>
[[File:TRANS_BR_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -4.0892 -2.4307 0.0033 0.0037 0.0038 0.9105
Low frequencies --- 17.7328 48.9885 72.9546
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>TRANS_BR_OPT_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

The energy of the isomer = -2352.41629 Hartrees = -6176269.4 kJ/mol

====Relative Energies====

ΔE = -2352.412629 - -2352.40631 = 0.006319 Hartrees = 16.6 kJ/mol

The isomer with chlorine as the bridging atom has a slightly lower energy indicating the isomer is more stable. This could be due to the chlorine being the bridging atom as it is in the same period as aluminium. Therefore, there is a larger orbital overlap and electron density isn't as diffuse as with bromine atoms. The electron density is shared better over the 3 centres and the bonds are shorter. Meaning the bond is stronger and the isomer is more stable.

=== AlCl2Br Molecule===
'''B3LYP/6-31G(d.p)LANL2DZ level'''

[[File:Monomer_summary_av4217.png]]

<pre>
Item Value Threshold Converged?
Maximum Force 0.000136 0.000450 YES
RMS Force 0.000073 0.000300 YES
Maximum Displacement 0.000681 0.001800 YES
RMS Displacement 0.000497 0.001200 YES
Predicted change in Energy=-7.984447D-08
Optimization completed.
-- Stationary point found.
</pre>

[[File:MONOMER1_FREQ_AV4217.LOG]]

<pre>
Low frequencies --- -0.0033 -0.0015 0.0032 1.3569 3.6367 4.2604
Low frequencies --- 120.5042 133.9178 185.8950
</pre>

<jmol><jmolApplet>
<title>Al2Br2Cl4 Molecule</title>
<color>black</color>
<size>200</size>
<uploadedFileContents>MONOMER1_FREQ_AV4217.LOG</uploadedFileContents>
</jmolApplet></jmol>

====Dissociation Energy====
E(AlCl2Br) = -1176.19014 Hartrees
E(