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== lab marking ==
You have a good working wiki. It would be good if you report values of wavenumber in your answers. Overall a very good attempt. If you have any specific questions, do email Prof. Hunt

== NH<sub>3</sub> ==
===Calculation Data===
Optimisation of NH<sub>3</sub> was performed using the following parameters:
{| class="wikitable"
|<b>Log file</b>|| AH_opf_pop.log
|-
|<b>Molecule</b>|| NH<sub>3</sub>
|-
|<b>Method</b>|| RB3LYP
|-
|<b>Basis set</b>|| 6-31G(d,p)
|-
|<b>Final energy</b>|| -56.55777 au
|-
|<b>RMS gradient</b>|| 0.000000
|-
|<b>Point group</b>|| C<sub>3V</sub>
|}

===Log file===
[[Media:AH_NH3_OPF_POP.LOG]]

===Convergence data===
The following data was collected from the log file, confirming convergence.
====Item table====
<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000000     0.000015     YES
 RMS     Force            0.000000     0.000010     YES
 Maximum Displacement     0.000003     0.000060     YES
 RMS     Displacement     0.000001     0.000040     YES
</pre>
====Low frequencies====
<pre>
 Low frequencies ---   -5.6864   -3.6131   -3.6124    0.0017    0.0048    0.0162
 Low frequencies --- 1089.3674 1693.9284 1693.9284
</pre>

===Optimised molecule===
====Molecule parameters====
* r(N-H): 1.02&Acirc;<br>
* &theta;(H-N-H): 106&deg;
====Molecular structure====
NH<sub>3</sub> top-down view

[[File:AH_nh3_opf.PNG]]

<jmol><jmolApplet>
<title>NH&#8323; 3D view</title>
<color>#8080cc</color>
<size>272</size>
<uploadedFileContents>AH_NH3_OPF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>


===Vibrational analysis and IR spectrum===
{| class="wikitable"
| <b>Mode</b> || 1 || 2 || 3 || 4 || 5 || 6
|-
| <b>Wavenumber (cm<sup>-1</sup>)</b> || 1089 || 1694 || 1694 || 3461 || 3590 || 3590
|-
| <b>Symmetry</b> || A<sub>1</sub> || E || E || A<sub>1</sub> || E || E
|-
| <b>Intensity</b> || 145 || 14 || 14 || 1 || 0 || 0
|}
[[File:AH NH3 OPF POP IR.PNG|700px]]

===Charge distribution===
{| class="wikitable"
| <b>Atom</b> || N || H
|-
| <b>Charge (e)</b> || -1.13 || +0.38
|}
[[File:AH_NH3_OPF_CDISTCONFIG.PNG]]

[[File:AH_NH3_OPF_CHARGEDIST.PNG]]


==cis-N<sub>2</sub>F<sub>2</sub> (Project molecule)==
===Calculation Data===
Optimisation of N<sub>2</sub>F<sub>2</sub> was performed using the following parameters:
{| class="wikitable"
|<b>Log file</b>|| AH_N2F2_OPTF_POP.LOG
|-
|<b>Molecule</b>|| N<sub>2</sub>F<sub>2</sub>
|-
|<b>Method</b>|| RB3LYP
|-
|<b>Basis set</b>|| 6-31G(d,p)
|-
|<b>Final energy</b>|| -309.01241 au
|-
|<b>RMS gradient</b>|| 0.000000
|-
|<b>Point group</b>|| C<sub>2V</sub>
|}

===Log file===
[[Media:AH_N2F2_OPTF_POP.LOG]]

===Convergence data===
The following data was collected from the log file, confirming convergence.
====Item table====
<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000001     0.000015     YES
 RMS     Force            0.000000     0.000010     YES
 Maximum Displacement     0.000001     0.000060     YES
 RMS     Displacement     0.000001     0.000040     YES
</pre>
====Low frequencies====
<pre>
 Low frequencies ---    0.0014    0.0022    0.0022    3.2225    4.3532    5.1001
 Low frequencies ---  347.8772  561.2472  771.6105
</pre>

===Optimised molecule===
====Molecule parameters====
* r(N-F): 1.39&Acirc;
* r(N=N): 1.22&Acirc;
* &theta;(F-N=N): 114&deg;
* &theta;(F-N=N-F): 0&deg;

====Molecular structure====
N<sub>2</sub>F<sub>2</sub> 2D view

[[File:AH_N2F2_OPTF.PNG]]
<jmol><jmolApplet>
<title>N&#8322;F&#8322; 3D view</title>
<color>#8080cc</color>
<size>272</size>
<uploadedFileContents>AH_N2F2_OPTF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>


===Vibrational analysis and IR spectrum===
====Data====
{| class="wikitable"
| <b>Mode</b> || 1 || 2 || 3 || 4 || 5 || 6
|-
| <b>Wavenumber (cm<sup>-1</sup>)</b> || 348 || 561 || 772 || 949 || 987 || 1637
|-
| <b>Symmetry</b> || A<sub>1</sub> || A<sub>2</sub> || B<sub>2</sub> || A<sub>1</sub> || B<sub>2</sub> || A<sub>1</sub>
|-
| <b>Intensity</b> || 1 || 0 || 75 || 75 || 81 || 21
|}
[[File:AH_N2F2_OPTF_POP_IR.PNG|700px]]
* The 3N-6 rule gives us an expected 6 vibrations (3 × 4 - 6 = 6).
* There are only 4 peaks on the IR spectrum because two of the vibrational modes have a negligible change in dipole moment, so they are not visible via IR spectroscopy.
* Vibrational mode 3 represents the asymmetric N-F stretching vibration.
* The highest energy mode is the N=N stretching vibration.

===Charge distribution===
cis-N<sub>2</sub>F<sub>2</sub> has a charge separation driven by the high electronegativity of the fluorine atoms.
{| class="wikitable"
| <b>Atom</b> || N || F
|-
| <b>Charge (e)</b> || +0.22 || -0.22
|}
[[File:AH_N2F2_OPTF_CDISTCONFIG.PNG]]

[[File:AH_N2F2_OPTF_POP_CHARGEDIST.png]]

===Molecular orbital analysis===
* MOs 1-4 correspond to the core orbitals of the atoms.
====Molecular Orbital 9====
The 9th molecular orbital of cis-N<sub>2</sub>F<sub>2</sub> can be represented as the in-phase addition of the p<sub>z</sub> orbitals on the N and F atoms.

[[File:AH_N2F2_OPTF_POP_MO9.PNG|x350px]][[File:AH_N2F2_OPTF_POP_LCAO.jpg|x350px]]

== BH<sub>3</sub>==
=== Calculation Data ===
Optimisation of BH<sub>3</sub> was performed using the following parameters:
{| class="wikitable"
|<b>Log file</b>|| AH_bh3_opt.log
|-
|<b>Molecule</b>|| BH<sub>3</sub>
|-
|<b>Method</b>|| RB3LYP
|-
|<b>Basis set</b>|| 6-31G(d,p)
|-
|<b>Final energy</b>|| -26.61532 au
|-
|<b>RMS gradient</b>|| 0.000002
|-
|<b>Point group</b>|| D<sub>3h</sub>
|}
===Log File===
[[Media:AH_BH3_OPT.LOG]]
===Convergence data===
The following data was collected from the log file, confirming convergence.
====Item table====
<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000004     0.000015     YES
 RMS     Force            0.000003     0.000010     YES
 Maximum Displacement     0.000017     0.000060     YES
 RMS     Displacement     0.000011     0.000040     YES
</pre>
====Low frequencies====
<pre>
 Low frequencies ---  -11.6940  -11.6861   -6.5543    0.0007    0.0280    0.4289
 Low frequencies --- 1162.9745 1213.1390 1213.1392
</pre>
Rounded to accurate significant figures:
<pre>
 Low frequencies ---  -12  -12   -7    0    0    0
 Low frequencies --- 1163 1213 1213
</pre>
===Optimised molecule===
====Molecule parameters====
* r(B-H): 1.192&Acirc;
* &theta;(H-B-H): 120.0&deg;

====Molecular structure====
BH<sub>3</sub> 2D view

[[File:AH_BH3_OPTF.png]]
<jmol><jmolApplet>
<title>BH&#8323; 3D view</title>
<color>#8080cc</color>
<size>272</size>
<uploadedFileContents>AH_BH3_OPT.LOG</uploadedFileContents>
</jmolApplet></jmol>

==NH<sub>3</sub>BH<sub>3</sub>==
=== Calculation Data ===
Optimisation of NH<sub>3</sub>BH<sub>3</sub> was performed using the following parameters:
{| class="wikitable"
|<b>Log file</b>|| AH_bh3_opt.log
|-
|<b>Molecule</b>|| BH<sub>3</sub>
|-
|<b>Method</b>|| RB3LYP
|-
|<b>Basis set</b>|| 6-31G(d,p)
|-
|<b>Final energy</b>|| -83.22469 au
|-
|<b>RMS gradient</b>|| 0.000001
|-
|<b>Point group</b>|| C<sub>3v</sub>
|}
===Log File===
[[Media:AH_NH3BH3_OPTF.LOG]]
===Convergence data===
The following data was collected from the log file, confirming convergence.
====Item table====
<pre>
         Item               Value     Threshold  Converged?
 Maximum Force            0.000002     0.000015     YES
 RMS     Force            0.000001     0.000010     YES
 Maximum Displacement     0.000017     0.000060     YES
 RMS     Displacement     0.000008     0.000040     YES
</pre>
====Low frequencies====
<pre>
 Low frequencies ---   -5.4185   -0.3223   -0.0476   -0.0003    1.1368    1.2200
 Low frequencies ---  263.2927  632.9711  638.4651
</pre>
Rounded to accurate significant figures:
<pre>
 Low frequencies ---   -5   0   0   0    1    1
 Low frequencies ---  263  633  638
</pre>
===Optimised molecule===
====Molecule parameters====
* r(B-H): 1.210&Acirc; 
* r(N-H): 1.018&Acirc;
* r(B-N): 1.668&Acirc;
* &theta;(H-B-H): 113.9&deg;
* &theta;(H-N-H): 107.9&deg;
* &theta;(N-B-H): 104.6&deg;
* &theta;(B-N-H): 111.0&deg;
* &theta;(H-B-N-H): 60.0&deg;

====Molecular structure====
BH<sub>3</sub> 2D view

[[File:AH_NH3BH3_OPTF.png]]
<jmol><jmolApplet>
<title>BH&#8323; 3D view</title>
<color>#8080cc</color>
<size>272</size>
<uploadedFileContents>AH_NH3BH3_OPTF.LOG</uploadedFileContents>
</jmolApplet></jmol>

==NH<sub>3</sub>-BH<sub>3</sub> association energy==
The energies of NH<sub>3</sub>BH<sub>3</sub> and its substituent fragments are as follows:
{| class="wikitable"
|<b>Molecule</b>|| <b>E (AU)</b>
|-
|NH<sub>3</sub>|| -56.55777
|-
|BH<sub>3</sub>|| -26.61532
|-
|NH<sub>3</sub>BH<sub>3</sub>|| -83.22469
|}

From this, we find the association energy:
&Delta;E = E(NH<sub>3</sub>BH<sub>3</sub>) - E(NH<sub>3</sub>) - E(BH<sub>3</sub>) = -0.05160 AU = -135kJ/mol