View source for MolMod2:ekm

== NH<sub>3</sub> - Ammonia ==

=== <u>Summary</u> ===

'''Calculation Method:''' RB3LYP

'''Basis Set:''' 6-31G(d,p)

'''Final Energy:''' -56.44397188 a.u.

'''Point Group:''' C3V

'''RMS Gradient:''' 0.00000485 a.u.

'''N-H Bond Length:''' 1.01798Å

'''H-N-H Bond Angle:''' 105.741°

<pre>    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
 </pre>

[[File:EKM_NH3_OPTF_POP.LOG]]

<jmol><jmolApplet>
  <title>A Jmol dynamic image of an optimised ammonia molecule </title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>EKM_NH3_OPTF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>

=== <u>Vibrations of NH<sub>3</sub></u> ===

[[File:Ekm_nh3_display_vibrations_tab.png|thumb|left|The Gaussview display vibrations tab for an optimised ammonia molecule.]]

'''-''' From the 3N-6 rule we would expect a total of 6 modes of vibration.

'''-''' 2 pairs of the modes are degenerate.

'''-''' There are 3 "bending" vibrations and 3 "stretching" vibrations.

'''-''' Mode 4 is highly symmetric.

'''-''' Mode 1 is the umbrella mode.

'''-''' 2 bands would be expected in an experimental spectrum of gaseous ammonia.

=== <u>Charge Distribution</u> ===

We would expect there to be a positive charge on the hydrogen atoms, and a negative charge on the nitrogen atom. This is because nitrogen is more electronegative than hydrogen, and therefore will draw electron density towards itself.

'''N charge:''' -1.125

'''H charge:''' +0.375

== N<sub>2</sub> - Nitrogen ==

=== <u>Summary</u> ===

'''Calculation Method:''' RB3LYP

'''Basis Set:''' 6-31G(d,p)

'''Final Energy:'''  -109.52412868 a.u.

'''Point Group:''' D*H

'''RMS Gradient:'''  0.00000060 a.u.

'''N-N Bond Length:''' 1.09200Å

'''Bond Angle:''' 180°

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

[[File:EKM_N2_OPTF_POP.LOG]]

<jmol><jmolApplet>
  <title>A Jmol dynamic image of an optimised nitrogen molecule </title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>EKM_N2_OPTF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>

=== <u>Vibrations of N<sub>2</sub></u> ===

[[File:Ekm_n2_display_vibrations_tab.png|thumb|left|The Gaussview display vibrations tab for an optimised nitrogen molecule.]]

'''-''' From the 3N-5 rule we would expect a total of 1 mode of vibration.

'''-''' There is 1 "stretching" vibration.

'''-''' No bands would be expected in an experimental spectrum of gaseous nitrogen.

=== <u>Charge Distribution</u> ===

We would expect there to be no overall charge on either nitrogen atom.

'''N charge:''' 0

== H<sub>2</sub> - Hydrogen ==

=== <u>Summary</u> ===

'''Calculation Method:''' RB3LYP

'''Basis Set:''' 6-31G(d,p)

'''Final Energy:''' -1.17853936 a.u.

'''Point Group:''' D*H

'''RMS Gradient:''' 0.00000017 a.u.

'''N-H Bond Length:''' 0.74279Å

'''Bond Angle:''' 180°

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

[[File:EKM_H2_OPTF_POP.LOG]]

<jmol><jmolApplet>
  <title>A Jmol dynamic image of an optimised hydrogen molecule </title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>EKM_H2_OPTF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>

=== <u>Vibrations of H<sub>2</sub></u> ===

[[File:Ekm_h2_display_vibrations_tab.png|thumb|left|The Gaussview display vibrations tab for an optimised hydrogen molecule.]]

'''-''' From the 3N-5 rule we would expect a total of 1 modes of vibration.

'''-''' There is 1 "stretching" vibration.

'''-''' No bands would be expected in an experimental spectrum of gaseous nitrogen.

=== <u>Charge Distribution</u> ===

We would expect there to be no overall charge on either hydrogen atom.

'''H charge:''' 0

== Reaction Energies ==

'''E(NH<sub>3</sub>):'''  -56.443972 a.u. 

'''2xE(NH<sub>3</sub>):''' -112.887944 a.u.

'''E(N<sub>2</sub>):'''  -109.524129 a.u. 

'''E(H<sub>2</sub>):'''  -1.178539 a.u. 

'''3xE(H<sub>2</sub>):''' -3.535618 a.u.

'''ΔE = 2xE(NH<sub>3</sub>) - [E(N<sub>2</sub>) + 3xE(H<sub>2</sub>)]:''' -0.0557907 a.u.

'''ΔE:''' -146.48 kJ mol<sup>-1</sup>

Since ΔE is positive, the reaction is endothermic. This suggests that the gaseous reactants are more stable than the product.

== CF<sub>4</sub> - Carbon Tetrafluoride ==

=== <u>Summary</u> ===

'''Calculation Method:''' RB3LYP

'''Basis Set:''' 6-31G(d,p)

'''Final Energy:''' -437.47627267

'''Point Group:''' TD

'''RMS Gradient:''' 0.00004048

'''C-F Bond Length:''' 1.32939 Å

'''F-C-F Bond Angle:''' 109.471°

<pre> Item               Value     Threshold  Converged?
 Maximum Force            0.000078     0.000450     YES
 RMS     Force            0.000042     0.000300     YES
 Maximum Displacement     0.000133     0.001800     YES
 RMS     Displacement     0.000071     0.001200     YES
</pre>

[[File:EKM_CF4_OPTF_POP.LOG]]

<jmol><jmolApplet>
  <title>A Jmol dynamic image of an optimised carbon tetrafluoride molecule </title>
  <color>black</color>
  <size>200</size>
  <uploadedFileContents>EKM_CF4_OPTF_POP.LOG</uploadedFileContents>
</jmolApplet></jmol>

=== <u>Vibrations of CF<sub>4</sub></u> ===

[[File:Ekm_cf4_display_vibrations_tab.png|thumb|left|The Gaussview display vibrations tab for an optimised carbon tetrafluoride molecule.]]

'''-''' From the 3N-6 rule, we would expect 9 modes of vibration.

'''-''' 1 pair of modes are degenerate, and 2 groups of 3 modes are degenerate.

'''-''' 8 modes are "bending" modes,and 1 is "stretching" modes.

'''-''' Mode 6 is highly symmetric.

'''-''' I would expect to see 1 band in an experimental spectrum of gaseous tetrafluoromethane.

=== <u>Charge Distribution</u> ===

We would expect there to be a strong positive charge on the carbon atom and negative charges on the fluorine atoms, owing to fluorine's strong electronegativity, resulting in electrongs being drawn away from the carbon nucleus to the fluorine nuclei. 

'''Charge on C:''' +1.407

'''Charge on F:''' -0.352



=== <u>Molecular Orbitals</u> ===

[[File:ekm_cf4_homo_visualisation.png|350px|left|thumb|A Gaussview visualisation of the HOMO for an optimised tetrafluoromethane molecule]]

[[File:ekm_cf4_lumo_visualisation.png|350px|left|thumb|A Gaussview visualisation of the LUMO for an optimised tetrafluoromethane molecule]]

[[File:ekm_cf4_mo8_visualisation.png|350px|left|thumb|A Gaussview visualisation of the 8th MO for an optimised tetrafluoromethane molecule]]

'''-''' The 8th molecular orbital is deep in energy and is occupied. 

[[File:ekm_cf4_mo16_visualisation.png|350px|left|thumb|A Gaussview visualisation of the 16th MO for an optimised tetrafluoromethane molecule]]

'''-'''The 16th molecular orbital is in the HOMO/LUMO energy region and is occupied.

[[File:ekm_cf4_mo24_visualisation.png|350px|left|thumb|A Gaussview visualisation of the 24th MO for an optimised tetrafluoromethane molecule]]

'''-'''The 24th molecular orbital is high in energy and is unoccupied.