The importance of polarizability in the modeling of solubility: Quantifying the effect of solute polarizability on the solubility of small nonpolar solutes in popular models of water

In recent work by Paschek [J. Chem. Phys. 120, 6674 (2004)] and others [see H. Docherty , J. Chem. Phys. 125, 074510 (2006) for a review] it has been suggested that, when coupled to a simple Lennard-Jones model for various small nonpolar solute molecules, the most common models of water (e.g., SPC/E and TIP4P) fail to reproduce quantitatively the solubility of small nonpolar solute molecules in water due in part to failing to account for polarization of the solute molecule. Given the importance of such systems as test-case prototype models of the solubility of proteins and biomolecules, in this work, we investigate the impact of using a polarizable solute model with the SPC/E, TIP3P, TIP4P, TIP4P-Ew, and TIP4P/2005 rigid water models. Specifically we consider Ne, Ar, Kr, Xe, and methane as solutes. In all cases we observe that the use of a polarizable solute improves agreement between experiment and simulations, with the best agreement seen for the largest solutes, Kr, CH(4), and Xe and the modern reparametrizations of the TIP4P model, i.e., the TIP4P-Ew and TIP4P/2005 models. (C) 2008 American Institute of Physics.