RichardZhang
Borane
Optimization of Borane(3-21G)
Optimization of Borane(6-31G)
The optimisation file is liked to here
| BH3 |
| Mode | Vibration | Intensity | Symmetry | IR Active | Type |
|---|---|---|---|---|---|
| 1 | 1163 | 93 | A2' | Yes | out-of-plane bend |
| 2 | 1213 | 14 | E' | Yes | bend |
| 3 | 1213 | 14 | E' | Yes | bend |
| 4 | 2582 | 0 | A1' | No | symmetric stretch |
| 5 | 2715 | 126 | E' | Yes | asymmetric stretch |
| 6 | 2715 | 126 | E' | Yes | asymmetric stretch |
There are less than six peaks in the spectrum even though there are obvious six vibrations. This is because the translation modes are degenerate each other, such as mode 2 and mod 3, mode 5 and mode 6. In addition, the vibration mode 4 is IR inactive, which therefore also missed in the IR spectrum.
No obvious differences can be observed between the real and LCAO MOs, which means that the ......
Association energy calculation
Optimization of Ammonia(6-31G)
1.RB3LYP/6-31G:
The optimisation file is liked to here
| Ammonia |
| Mode | Vibration | Intensity | Symmetry | IR Active | Type |
|---|---|---|---|---|---|
| 1 | 1694 | 145 | A | Yes | out-of-plane bend |
| 2 | 1694 | 13 | E | Yes | bend |
| 3 | 1694 | 13 | E | Yes | bend |
| 4 | 3461 | 1 | A1 | No | symmetric stretch |
| 5 | 3589 | 0 | E | No | asymmetric stretch |
| 6 | 3589 | 0 | E | No | asymmetric stretch |
Optimization of Ammonia Borane(6-31G)
1.RB3LYP/6-31G:
The optimisation file is liked to here
| Ammonia Borane |
Calculation process
E(NH3)=-56.55776863 a.u ≈ -1.48492x10^5 kJ/mol
E(BH3)=-26.61532360 a.u ≈ -6.9879x10^4 kJ/mol
E(NH3BH3)=-83.22469012 a.u ≈ -2.18506x10^5 kJ/mol
ΔE = E(NH3BH3)-[E(BH3)+E(NH3)] = -2.18506x10^5+(6.9879x10^4+1.48492x10^5) ≈ -135 kJ/mol
The value of association energy is a negative value, which means the B-N dative bond is stronger than the ?
Borone tribromide
1. RB3LYP/GEN:
The optimisation file is liked to here
| Boron tribromide |
| Mode | Vibration | Intensity | Symmetry | IR Active | Type |
|---|---|---|---|---|---|
| 1 | 156 | 145 | E' | NO | asymmetric stretch |
| 2 | 156 | 13 | E' | NO | asymmetric stretch |
| 3 | 268 | 13 | A1' | NO | symmetric stretch |
| 4 | 378 | 1 | A2 | Yes | out-of-plane bend |
| 5 | 763 | 0 | E' | Yes | bend |
| 6 | 763 | 0 | E' | Yes | bend |
The pps-optimisation of BBr3: DOI:10042/202437
The pps-frequency of BBr3: DOI:10042/202439
Project of aromaticity
Optimization of Benzene
1.RB3YLP/6-31G:
The optimisation file is liked to here
| Benzene |
Optimization of Borazine
1.RB3YLP/6-31G:
The optimisation file is liked to here
| Borazine |
The Natural Bond Orbital analysis
| Atom | Charge/a.u | Electronegativity |
|---|---|---|
| c | -0.239 | 2.5 |
| H | 0.239 | 2.2 |
| Atom | Charge/a.u | Electronegativity |
|---|---|---|
| B | 0.747 | 2.0 |
| N | -1.102 | 3.04 |
| H | 0.432 | 2.2 |
| H | -0.077 | 2.2 |
According to the diagrams and tables shown above, it is obvious that the charge density in the benzene is evenly distributed. However, the charge of the carbon is 0.239 a.u and the charge of the carbon is -0.239, which is a big difference. This is mainly because of the electronegativity difference between H(2.5) and C(2.2)
| MOs of Benzene | MOs of Borazine | Describtion |
|---|---|---|
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The Molecular orbitals are MO no.14 for benzene and MO no.15 for Borazine. The energy of benzene is -0.43854, which is almost the same as the energy of borazine(-0.43197). |
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