Table 3.
The A-A’ energies of CH3 and various CH2 groups in the straight-chain homologous series CH4 to C8H18. Units: kJ/mol. Method: 2PDM-M/CCSD/uncontracted 6–31 + G(d, p). Grid is (15,15)
| Molecule | CH3 | CH2(-CH3)a | CH2(-CH2-CH3) | CH2(-CH2-CH2-CH3) |
|---|---|---|---|---|
| CH4 | 153.2 | - | - | - |
| C2H6 | 173.6 | - | - | - |
| C3H8 | 177.0 | 163.4 | - | - |
| C4H10 | 178.0 | 165.2 | - | - |
| C5H12 | 178.4 | 166.0 | 167.4 | - |
| C6H14 | 178.5 | 166.3 | 168.2 | - |
| C7H16 | 178.5 | 166.4 | 168.5 | 169.2 |
| C8H18 | 178.6 | 166.4 | 168.5 | 169.1 |
a We designate a group by referring to the smallest chain that it belongs to. For example, in C4H10 there is a “CH2(-CH2-CH3)” methylene group but this CH2 is also the methylene that occurs in CH2(-CH3). Because the latter chain is smaller it is the only reference point giving a non-empty entry in the table