Table 1. Classical and Zero-Point Vibrational Energy Corrected (Adiabatic) Energies of X– + CH3Y → P + Q (X, Y = F, Cl, Br, I) Reaction Channels Obtained at the CCSD(T)-F12b/aug-cc-pVQZ(-PP)//CCSD(T)-F12b/aug-cc-pVTZ(-PP) Level of Theory in kcal/mola.
| Q | Y– | HX | H– | XHY– | XY | XY– |
|---|---|---|---|---|---|---|
| P | CH3X | CH2Y– | CH2XY | 1CH2 | CH3– | CH3 |
| F/F | 0.0(0.0) | 42.2(37.8) | 46.3(42.3) | 55.3(47.5) | 155.0(149.4) | 87.0(81.5) |
| Cl/Cl | 0.0(0.0) | 68.6(63.0) | 91.4(86.1) | 83.5(73.6) | 112.6(107.5) | 57.8(53.1) |
| Br/Br | 0.0(0.0) | 74.6(68.7) | 100.7(95.1) | 88.7(78.9) | 104.6(99.6) | 46.4(41.9) |
| I/I | 0.0(0.0) | 78.8(72.6) | 108.3(102.4) | 95.8(85.9) | 94.7(90.0) | 37.0(32.8) |
| F/Cl | –32.7(−31.7) | 28.7(24.8) | 54.5(50.3) | 43.6(37.6) | 103.8(99.0) | 52.7(48.1) |
| F/Br | –40.9(−39.5) | 24.1(20.3) | 56.1(52.0) | 38.9(33.2) | 91.1(86.5) | 40.2(35.9) |
| F/I | –47.8(−46.0) | 18.7(15.2) | 58.3(54.2) | 35.6(30.2) | 73.3(69.1) | 26.3(22.5) |
| Cl/Br | –8.2(−7.7) | 63.9(58.5) | 92.0(86.8) | 80.0(71.8) | 104.3(99.4) | 47.6(43.2) |
| Cl/I | –15.1(−14.3) | 58.6(53.4) | 92.9(87.7) | 77.2(69.5) | 93.3(88.7) | 37.7(33.6) |
| Br/I | –6.9(−6.5) | 69.3(63.6) | 101.3(95.7) | 87.2(78.6) | 95.0(90.3) | 37.5(33.4) |
a
In the case of identity reactions, X and Y are the same; otherwise, Y denotes the halogen with the higher atomic number.