Hydrophobic interaction and hydrogen-bond network for a methane pair in liquid water

Li et al. 10.1073/pnas.0610945104.

Supporting Information

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SI Figure 8
SI Figure 9
SI Figure 10
SI Figure 11
SI Figure 12
SI Figure 13
SI Table 1
SI Text

SI Figure 8

Fig. 8. Convergence of the time average of the constraint force between the two methanes separated by a distance r. Each plot represents a backward time average, starting from the last simulation. (a) r = 5.6 Å. (b) r = 4.4 Å for 6-ps average. (c) Another simulation at r = 4.4 Å for 10-ps average. (d) r = 4.4 Å, MD simulation with 139 water molecules. The time-averaged forces for c and d are within 10^-4 a.u.

SI Figure 9

Fig. 9. Free energy of transfer of n-alkanes from hydrocarbon solvent to water at room temperature T = 298 K. Solubility data are taken from McAuliffe [McAuliffe C (1966) J Phys C 70:1267-1275].

SI Figure 10

Fig. 10. Solubility (measured by molar fraction) data [Lide DR, ed (2003) CRC Handbook of Chemistry and Physics (CRC, Boca Raton, FL), 84th Ed] between hydrocarbon gas phase and water. The temperature-dependent fitting curves are shown as dashed lines.

SI Figure 11

Fig. 11. Transfer free energy from gas phase to water. (Left: T = 298 K. Right: T = 343 K). The transfer free energy per unit area (slope) increases by 39% from T = 298 K to T = 343 K.

SI Figure 12

Fig. 12. The force between two methanes in vacuum derived from density-functional theory and Lennard-Jones potentials. At larger distances (>4.4 Å), density-functional theory gives almost zero force between two methanes.

SI Figure 13

Fig. 13. Illustration of the buried area between two methane molecules.