Table 2.
Comparison of total solvation energies (kcal/mol) for small alkane solutes
| Compound | WCA 1.13 | WCA 1.04 | opls | amber | Exp. |
|---|---|---|---|---|---|
| Methane | 2.82 | 2.10 | 2.40 | 2.69 | 2.00 |
| Ethane | 3.53 | 2.55 | 2.63 | — | 1.83 |
| Propane | 3.99 | 2.77 | 2.89 | 3.02 | 1.96 |
| Butane | 4.33 | 2.96 | 3.21 | 3.19 | 2.08 |
| Pentane | 5.13 | 3.50 | 3.78 | — | 2.33 |
| Hexane | 5.56 | 3.79 | 3.78 | — | 2.49 |
| Isobutane | 4.55 | 3.04 | 3.03 | 3.27 | 2.52 |
| 2-Methylbutane | 5.04 | 3.24 | 3.51 | — | 2.38 |
| Neopentane | 4.97 | 3.37 | 3.23 | — | 2.50 |
| Cyclopentane | 3.89 | 2.40 | 2.80 | — | 1.20 |
| Cyclohexane | 4.83 | 2.97 | 2.34 | — | 1.23 |
WCA energy values were obtained by using the methods described with σs = 1.13 and 1.04 Å. opls energies were taken from Gallicchio et al. (35) by using values in table 2 of their paper. amber energies are from Shirts et al. (64), “van der Waals” values in table II of their paper. Experimental (Exp.) values are from table VII of Cabini et al. (65).