Table 20.
The atomic energies of ethanol in various conformations. One dihedral angle is fixed and the other geometric parameters optimised. The atom labels refer to the eclipsed conformation. Grid is (15,15). Note here we eclipse along the C-C bond, while in Table 17 (methanol) we eclipsed along the C-O bond. Method: 2PDM-M/CCSD(T)/uncontracted 6–31 + G(d, p). Unit: kJ/mol
| Atom/conformation | eclipsed | 20.0 | 40.0 | minimum | average | SD |
|---|---|---|---|---|---|---|
| C1 (CH3) | 90.6 | 90.3 | 90.1 | 89.8 | 90.2 | 0.3 |
| C2 (CH2) | 105.2 | 105.1 | 104.7 | 104.6 | 104.9 | 0.2 |
| O3 (-C2, eclipse H7) | 156.5 | 156.4 | 156.0 | 156.0 | 156.2 | 0.2 |
| H4 (-O3, trans to CH3) | 24.0 | 24.0 | 23.9 | 23.9 | 23.9 | 0.1 |
| H5 (-C2) | 33.1 | 33.1 | 33.1 | 33.1 | 33.1 | 0.0 |
| H6 (-C2) | 33.1 | 33.1 | 33.1 | 33.1 | 33.1 | 0.0 |
| H7 (-C1, eclipse O) | 29.5 | 29.6 | 29.9 | 30.1 | 29.8 | 0.2 |
| H8 (-C1, eclipse H5) | 30.5 | 30.7 | 30.8 | 30.8 | 30.7 | 0.1 |
| H9 (-C1, eclipse H6) | 30.5 | 30.3 | 30.3 | 30.1 | 30.3 | 0.1 |