8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P2.34Tue 611:23-14:00Towards a molecular theory of hydrophobic hydration:hard spheres in primitive waterJan Jirsák 1 and Ivo Nezbeda 11 Institute of Chemical Process Fundamentals, Academy of Sciences of the CzechRepublic, Rozvojová 135/2, 165 02, Prague 6, Czech RepublicRecently obtained equations of state (EoS’s) for mixtures of hard spheres (HS’s) and pseudo-hardbodies (PHB’s) are employed to describe hydration of simple nonpolar solutes. Monte Carlodata [1] on compressibility factor of HS/PHB mixtures for several diameter ratios have beenparametrized into analytical EoS’s. The resulting expressions are combined with perturbationterms for the primitive model of water derived within the thermodynamic perturbation theoryof the second order [2]. Thermodynamic characteristics of solvation, such as the Gibbs energychange and related quantities, are evaluated as functions of temperature. Trends typical forhydrophobic hydration are recovered. Qualitative correctness of the theoretical results suggeststhat, despite its simplicity, the underlying molecular model captures the essence of hydration ofnonpolar solutes. This work has been financially supported by the Grant Agency of the Academyof Sciences of the Czech Republic (Grant. No. IAA400720802).[1] M. Rouha, I. Nezbeda, Mol. Phys. 106, 2481 (2008). Raw data by private communication.[2] L. Vl˘cek, J. Slovák, I. Nezbeda, Mol. Phys. 101, 2921 (2003).34