Rep:Mod:qwe107
NH3
Optimisation
Molecule- NH3
Calculation method- RB3LYP
Basis set- 6-31G(d.p)
Final energy E(RB3LYP) in atomic units (au)- -56.55776873
RMS gradient- 0.00000485
point group- C3V
Optimised bond length- 1.01798 nm
Optimised 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
The optimisation file is liked here
Frequency Analysis
Expected modes- (3X4)-6=6
Degenerate modes- modes 2 and 3 and modes 5 and 6
Bending vibrations- modes 1, 2, 3
Bond stretch vibrations- 4, 5, 6
Highly symmetric- mode 4
Umbrella mode- mode 1
Number of bands expected in an experimental spectrum- 3 however one has very flow intensity
Charge Analysis
Charge on the N-atom- -1.125
Charge on the H-atom- +0.375
The expected charges are negative on the N-atom and positive on the H-atom as Nitrogen is more electronegative and so will attract a higher charge density.
N2
Optimisation
Molecule- N2
Calculation method- RB3LYP
Basis set- 6-31G(d.p)
Final energy E(RB3LYP) in atomic units (au)- -109.52412868
RMS gradient- 0.00000365
point group- D∞h
Optimised bond length- 1.10550 nm
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
The optimisation file is liked here
Frequency Analysis
There is no peaks on the IR spectrum as the vibration does not have a change in dipole moment.
H2
Optimisation
Molecule- H2
Calculation method- RB3LYP
Basis set- 6-31G(d.p)
Final energy E(RB3LYP) in atomic units (au)- -1.17853936
RMS gradient- 0.00002276
point group- D∞h
Optimised bond length- 0.74274 nm
Item Value Threshold Converged? Maximum Force 0.000039 0.000450 YES RMS Force 0.000039 0.000300 YES Maximum Displacement 0.000052 0.001800 YES RMS Displacement 0.000073 0.001200 YES
The optimisation file is liked here
Frequency Analysis
There is no peak on the IR spectrum as the vibration does not have a change in dipole moment.
Reaction energy for the formation of NH3
E(NH3)= -56.55776873 au
2*E(NH3)= -113.11553746 au
E(N2)= -109.52412868 au
E(H2)= -1.17853936 au
3*E(H2)= -3.53561808 au
ΔE=2*E(NH3)-[E(N2)+3*E(H2)]= -0.05579070 au
ΔE= -146.48 KJ/mol
Product, NH3, is more stable
[BH4]-
Optimisation
BH |
Molecule- BH4-
Calculation method- RB3LYP
Basis set- 6-31G(d.p)
Final energy E(RB3LYP) in atomic units (au)- -27.24992701
RMS gradient- 0.00000671
point group- TD
Optimised bond length- 1.23933 nm
Optimised bond angle- 109.471°
Item Value Threshold Converged? Maximum Force 0.000013 0.000450 YES RMS Force 0.000007 0.000300 YES Maximum Displacement 0.000065 0.001800 YES RMS Displacement 0.000035 0.001200 YES
The optimisation file is liked here
Frequency Analysis
Expected modes- (3X5)-6=9
Degenerate modes- modes 1, 2 and 3, modes 4 and 5 and modes 6, 7 and 8
Bending vibrations- modes 1 to 5
Bond stretch vibrations- 6 to 9
Symmetric- modes 4, 5 and 9
Number of bands expected in an experimental spectrum- 2
Charge Analysis
Charge on the B-atom- -0.097
Charge on the H-atom- -0.226
Molecular orbitals
| Molecular orbital | Formation |
|---|---|
|
Antibonding molecular orbital between the Hydrogen 1s orbital and the Boron 2s orbital. It is deep in energy. This does not contribute to bonding in the molecule. |
|
Bonding molecular orbital between the Hydrogen 1s orbital and the Boron 2s orbital. It is The second lowest in energy. |
|
There are three of this orbital, all equal in energy. One is along each axis. This is the the mixture of a 2p orbital from the Boron and the 1s orbitals on the Hydrogens. The two Hydrogens on each side match the phase of the 2p orbital on the same side. This is the HOMO. |
|
This is the LUMO and has a positive value. This is the antibonding orbital between the Boron 2p orbital and the Hydrogens 1s orbitals. Instead on the Hydrogen orbitals matching phase with the 2p on the same side, the 2p is flipped and so they match phase with the opposing side. Again there are three of these, one on each axis. |
|
This is also an unoccupied orbital with a positive value. This is the antibonding orbital between the 2s orbitals on the Hydrogens and the 2s orbital on the Boron. |
H2SiO
Optimisation
Molecule- H2SiO
Calculation method- RB3LYP
Basis set- 6-31G(d.p)
Final energy E(RB3LYP) in atomic units (au)- -365.90001403
RMS gradient- 0.00000941
point group- CS
Optimised Si=O bond length- 1.53172
Optimised O-Si-H bond angle- 124.158°
Optimised Si-H bond length- 1.48652
Optimised H-Si-H bond angle- 111.686°
Item Value Threshold Converged? Maximum Force 0.000023 0.000450 YES RMS Force 0.000009 0.000300 YES Maximum Displacement 0.000023 0.001800 YES RMS Displacement 0.000017 0.001200 YES
The optimisation file is liked here
Frequency Analysis
Expected modes- (3X4)-6=6
Degenerate modes- none
Bending vibrations- modes 1 to 4
Bond stretch vibrations- modes 5 and 6
Symmetric- none
Number of bands expected in an experimental spectrum- 6 however some are very close and may merge. On the predicted spectrum from Gaussian 5 resolved peaks can be seen.
Charge Analysis
Charge on the O-atom- -0.502
Charge on the H-atom- -0.090
Charge on the Si-atom- +0.681