View source for Victor's 2nd modelling

== NH3 optimization ==

=== General information===
H-N-H bond angle: 105.741°

N-H bond length: 101.798 pm

Charges: N has a higher electronegativity than H, thus one would expect a negative charge for N and a positive charge for H. Indeed calculations of GaussView yield the following charges: N: -1.125 ; H:0.375

===Summary table===

[[File:SummarytableNh3.PNG]]

===Item table with link to LOG file===

Item               Value     Threshold  Converged?
 Maximum Force            0.000004     0.000450     YES
 RMS     Force            0.000004     0.000300     YES
 Maximum Displacement     0.000072     0.001800     YES
 RMS     Displacement     0.000035     0.001200     YES
 Predicted change in Energy=-5.986258D-10
 Optimization completed.


[[File:VLANDGRAF_NH3_OPT.LOG]]

====JSmol of optimised NH<sub>3</sub>  molecule====

<jmol><jmolApplet>
  <title>optimised NH3 molecule</title>
  <color>black</color>




  <size>200</size>
  <uploadedFileContents>VLANDGRAF_NH3_OPT.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Vibrations===

[[File:Nh3_vibrations.PNG]]

===Answers to question===
1. As there are four atoms in an NH3 molecule the 3N-6 rule predicts 6 modes.

2. Mode 2,3 and 5,6 have the same energy respectively: Their absorption frequencies are identical, thus they have to have the same energy as E=hf, where h is the Planck constant and f is the frequency.

3. 1,2,3 are bending modes, 4,5,and 6 are stretching modes. This can be deduced from the GaussView animation.

4. Mode 4 looks highly symmetric in the Gaussview animation.

5. The umbrella mode is mode 1 as can be seen from the animation on GaussView.

6. One would expect six absorptions but there are four as there are two pairs of identical absorption frequencies.



==N2 optimisation==

===General information===

Bond length of N<sub>2</sub> : 110.5 pm

Bond angle: 180° as it is a linear molecule.

===Summary table===

[[File:S_N2.png]]

===item table with link to LOG file===

[[File:itemN2.png]]

[[File:N2 OPTIMIZATION VICTOR LANDGRAF.LOG]]

====JSmol of optimised N<sub>2</sub> ====

<jmol><jmolApplet>
  <title>opt. N2 molecule</title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>N2_OPTIMIZATION_VICTOR_LANDGRAF.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Vibrations===

[[File:vibrationsN22.png]]

The 3N-5 rule predicts only one vibration as the N2 molecule contains 2 atoms.
There is no dipole in N<sub>2</sub> which is why it cannot be seen in IR spectroscopy (i.e the intesnity is 0).

==H2 optimisation==

===General information===

Bond length of optimized molecule: 74.274 pm

Bond angle: 180° as it is a linear molecule.

Charges: Charges are the same as H<sub>2</sub>  contains two identical H atoms.

===Summary table===

[[File:H2s.png]]

===Item table with LOG file===

[[File:h2optimization.png]]

[[File:H2OPTIMIZATION.LOG]]


====JSmol of optimised H2 molecule====



<jmol><jmolApplet>
  <title>opt. H2 molecule</title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>H2OPTIMIZATION.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Vibrations===
[[File:H2vibrationsVictor.PNG]]

This consists with the expectation as the 3N-5 rule predicts 1 mode for the H2 molecule as it contains 2 atoms.
There is no dipole in H<sub>2</sub> which is why it cannot be seen in IR spectroscopy (i.e the intesnity is 0).

==Haber-Bosch process==


N<sub>2</sub> + 3 H<sub>2</sub>  --> 2 NH<sub>3</sub> 


E(NH<sub>3</sub> )= -56.55776873 au

2*E(NH<sub>3</sub> )= -113.1155375 au

E(N<sub>2</sub> )= -109.52412868 au

E(H<sub>2</sub> )= -1.17853936 au

3*E(H<sub>2</sub> ) = -3.53561808 au


ΔE=2 E(NH<sub>3</sub> )-[(E(N<sub>2</sub> )+3 E(H<sub>2</sub> )]


ΔE= -113.1155375 au - (-109.5241287-3.5356180)au = 0.0552280 au = -145.00 kJ/mol

The energy necessary to convert H<sub>2</sub>  gas and N<sub>2</sub>  gas into NH<sub>3</sub>  gas is -145.00 kJ/mol. This shows that the energy required to break the N<sub>2</sub>  and H<sub>2</sub>  bonds is less than the energy released forming the bonds that make NH<sub>3</sub> . Thus the product is more stable.


ΔH<sub>f</sub> for the formation of 2 NH<sub>3</sub> is -92 kJ/mol <ref name="enthalpy" />
for 723K and 100 atm of pressure. The diverge because the conditions GaussView uses for its calculations are different and because the entropy changes are not taken into account properly by GaussView.


====Reference====
<references>
<ref name = "enthalpy"> Rob Davis <i>Periodicity</i> [Lecture] Imperial College, March 2016. </ref>
</references>

==ClF my small molecule==

===General information===

Bond length: 166.434 pm

Bond angle: 180° as it is a linear molecule.

Charges: -0.309 (F) and +0.309 (Cl) which is consistent with the expectations as F is more electronegative.

===Summary table===

[[File:ClFsV.PNG]]


===Item table with link to LOG file===

[[File:ClFitemV.PNG]]


Link to LOG file: [[File:CLF OTPIMIZATION.LOG]]

====JSmol of optimised ClF molecule====

<jmol><jmolApplet>
  <title>optimized ClF molecule</title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>CLF_OTPIMIZATION.LOG</uploadedFileContents>
</jmolApplet></jmol>

===Vibrations===

ClF has 1 mode as the 3N-5 rule predicts (N=#of atoms in molecule)

Light absorption frequency: 781.00 Hz

==5 Orbitals==
===Orbital1===

[[File:Orbital7victor.PNG]]

Bonding sigma molecular orbital (MO) where  one 3s of Cl and the 2s of F overlap. Energetically it is in the HOMO/LUMO region (-1.2186 au) compared to the HOMO -0.32855 au. It is occupied and would thus form a sigma bond between the two atoms but there is an occupied anti bonding MO (see below) which "cancels" this bond. It can be seen that the 2p  atomic orbital (AO) of F contributes more to this bonding MO. This in the case because it is lower in energy than the 3p AO of Cl it interacts with.

===Orbital2===

[[File:Orbital8victor.PNG]]

Anti bonding sigma MO where 3s AO of Cl and the 2s AO of F overlap. It is energetically close to the HOMO/LUMO region, too.  It is occupied and thus "cancels" the bond that would be formed by the occupied bonding MO above. It can be seen that the 3s AO of Cl contributes more to the anti bonding MO as it is higher in energy than the 2s AO of F.

===Orbital3===

[[File:Orbital9victor.PNG]]

Bonding sigma MO formed by overlap of 3p AO of Cl and 2p AO of F. It is in the HOMO/LUMO region, energy wise. The 2p AO of F contributes more to this bonding MO for reasons explained above. It is occupied and forms a bond between the two atoms. There is no occupied anti bonding orbital that would "cancel" this bond thus it consists.
 
===Orbital4===

[[File:Orbital10victor.PNG]]

Pi bonding orbital formed by overlap of 3p atomic orbital of Cl and 2p atomic orbital of F. It is in the HOMO/LUMO region, energy wise and occupied. This MO would form a bond but there is an occupied anti bonding MO that "cancels" the bond. 

===Orbital5===

[[File:Orbital1victor.PNG]]

Pi anti bonding MO formed by overlap of 3p AO of Cl and 2p AO of F out of phase. Energetically it is in the HOMO/LUMO region. It is occupied and thus cancels the bond that would be formed by the occupied pi bonding molecular orbital above. It can be seen that the 3p AO of Cl contributes more to the anti bonding MO as it is higher in energy than the 2p AO of F.