G.M. Schütz, I. Ispolatov¹, G.T. Barkema² and B. Widom^1
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, USA
²Instituut voor Theoretische Fysica, Universiteit Utrecht, The Netherlands

We establish the equivalence of various lattice models of the hydrophohic interaction with the Ising model in a magnetic field with temperature-dependent strength. In order to capture the effect of symmetries of the solvent particles we introduce an extended model which is not of the Ising type. Our results for the solubility and the solvent-mediated part of the potential of mean force between solute particles suggest that an increase in symmetry enhances the solubility, but decreases the amplitude and range of the attractive force. This weakening of the hydrophohic effect observed in the model is in agreement with the notion that the effect is entropic in origin.