533g The Importance of Polarizability In the Modeling of Solubility: Quantifying the Effect of Solute Polarizability on the Solubility of Small Non-Polar Solutes In Popular Models of Water

Peter J. Dyer, Hugh Docherty, and Peter T. Cummings. Department of Chemical Engineering, Vanderbilt University, Nashville, TN 37235-1604

In recent work by Paschek (D. Paschek JCP 2004, 6674) and others (see H. Docherty et al. JCP 2006 074510 for a review) it has been suggested that, when coupled to a simple Lennard-Jones (LJ) model for various small non-polar solute molecules, the most common models of water (e.g. SPC/E and TIP4P) fail to reproduce quantitatively the solubility of small non-polar 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 the use of a polarizable solute improves agreement between experiment and simulations, with the best agreement seen for the largest solutes, Kr, CH4 and Xe and the recent reparameterizations of the TIP4P model, i.e. the TIP4P-Ew and TIP4P/2005 models.