Chemical potentials of hard solutes in hard sphere fluids: Monte Carlo simulations and analytical approximations

This thesis is a contribution to the understanding of solvent effects on the thermodynamic properties of molecules. Monte Carlo measurements of the chemical potentials of hard solutes of different conformations dissolved in hard sphere fluids are reported. These are compared with analytical expressions derived from the hard fluid (HF) model, performed as a function of solute size and solvent density. An excluded volume approximation, which is exact at low density, is found to compare favorably with simulation results for solutes of low asymmetry. This equates the chemical potential of an arbitrary shaped hardbody solute with that of a sphere of the same excluded volume. For solutes of high asymmetry systematic deviations from the excluded volume approximation are found. New analytical relations between a solutes effective hard sphere diameter and its asymmetry are suggested. This excluded-volume-anisotropy (EVA) model yields quantitative accurate chemical potential predictions for hardbody solutes of arbitrary size and shape, up to liquid densities