Syk2017
Part 1
| Name of molecule | NH3 |
| Calculation methods | B3LYP |
| Basis set | 6-31G |
| E(B3LYP) | -56.55776873 au |
| The point group | C3V |
| Bond length | 1.01798 Å |
| Bond angle | 105.741 |
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=-5.986272D-10
Optimization completed.
-- Stationary point found.
test molecule |
The optimisation file is linked to here
Part 2
• There are 4 modes of vibration according to the '3N-6 rule'.
• Mode 2 and 3 are degenerates.
• Mode 5 and 6 are degenerates.
• Mode 1, 2 and 3 are bending vibrations.
• Mode 4, 5 and 6 are bond stretching.
• Mode 1 and 4 are highly symmetric.
• Mode 1 is the umbrella mode
• 2 bands are shown
| charge on N | -1.125 |
| charge on H | 0.375 |
• Negative charge was expected for N, and positive charge was expected for H.
• This is because N has high electronegativity, forming a permanent partial negative charges as it attracts electrons.
Part 3
N2 molecule optimisation
| Name of molecule | N2 |
| Calculation methods | B3LYP |
| Basis set | 6-31G |
| E(B3LYP) | -109.52412868 au |
| The point gruop | D∞h |
| Bond Length | 1.10550 Å |
| Bond angle | 180 |
| number of vibration modes | 1 |
Item Value Threshold Converged?
Maximum Force 0.000006 0.000450 YES
RMS Force 0.000006 0.000300 YES
Maximum Displacement 0.000002 0.001800 YES
RMS Displacement 0.000003 0.001200 YES
Predicted change in Energy=-1.242352D-11
Optimization completed.
-- Stationary point found.
• 1 band, 0 IR
The optimisation file is linked to here
H2 molecule optimisation
| Name of molecule | H2 |
| Calculation methods | B3LYP |
| Basis set | 6-31G |
| E(B3LYP) | -1.17853930 au |
| The point gruop | D∞h |
| Bond Length | 0.74309 Å |
| Bond angle | 180 |
| number of vibration modes | 1 |
Item Value Threshold Converged?
Maximum Force 0.000211 0.000450 YES
RMS Force 0.000211 0.000300 YES
Maximum Displacement 0.000278 0.001800 YES
RMS Displacement 0.000393 0.001200 YES
Predicted change in Energy=-5.852867D-08
Optimization completed.
-- Stationary point found.
• 1 band, 0 IR
The optimisation file is linked to here
Energy Calculation
• E(NH3)= -56.55776873 au
• 2*E(NH3)= -112.1155375 au
• E(N2)= -109.52412868 au
• E(H2)= -1.17853930 au
• 3*E(H2)= -3.53561790 au
• ΔE=2*E(NH3)-[E(N2)+3*E(H2)]= 0.94420908 au
• -146.45106 kJmol-1
• Positive energy change. Therefore, reactants are more stable.
Part 4
Cl2 molecule optimisation
| Name of molecule | Cl2 |
| Calculation methods | B3LYP |
| Basis set | 6-31G |
| E(B3LYP) | -920.34987887 au |
| The point group | D∞h |
| Bond Length | 2.04161 Å |
| Bond angle | 180 |
| number of vibration modes | 1 |
Item Value Threshold Converged?
Maximum Force 0.000002 0.000450 YES
RMS Force 0.000002 0.000300 YES
Maximum Displacement 0.000006 0.001800 YES
RMS Displacement 0.000008 0.001200 YES
Predicted change in Energy=-1.226168D-11
Optimization completed.
-- Stationary point found
• 1 band, 0 IR
test molecule |
The optimisation file is liked to here
Cl2 molecular orbitals
• HOMO
• high in energy
• occupied by a electron pair
• π* orbital
• 2 degenerate orbitals
• 3P orbitals, out of phase
• relatively high in energy
• occupied by a electron pair
• π orbital
• 2 degenerate orbitals
• 3P orbitals, in phase
• relatively high in energy
• occupied by a electron pair
• σ orbital
• 1 degenerate orbitals
• 3P orbitals, in phase
• relatively high in energy
• occupied by a electron pair
• σ* orbital
• 1 degenerate orbitals
• 3S orbitals, Out of phase
• relatively low in energy
• occupied by a electron pair
• non-bonding
• 3 degenerate orbitals
• 2P orbitals, in phase
Part 5
HCl optimisation
| Name of molecule | HCl |
| Calculation methods | B3LYP |
| Basis set | 6-31G |
| E(B3LYP) | -460.80077875 au |
| The point group | C∞v |
| Bond Length | 1.28599 Å |
| Bond angle | 180 |
| charge on Cl | -0.185 |
| charge on H | 0.185 |
Item Value Threshold Converged?
Maximum Force 0.000090 0.000450 YES
RMS Force 0.000090 0.000300 YES
Maximum Displacement 0.000139 0.001800 YES
RMS Displacement 0.000197 0.001200 YES
Predicted change in Energy=-1.270754D-08
Optimization completed.
-- Stationary point found.
• 1 band, 1 IR
test molecule |
The optimisation file is liked to here