A polarizable water model for calculation of hydration energies

Abstract

A molecular model for electronic polarization of water is defined, consisting of interacting point dipole polarizabilities in an electric field generated by atomic point charges, which represent the gasphase dipole moment of water molecules. The induced dipole equations are solved self consistently. The model has been implemented in a Monte Carlo hydration simulation program, and its computational performance is discussed. Results of calculations of hydration and protonation energies of amines (including glycine) are presented and discussed, together with results for the water dimer and for liquid water. Solvent induction appears significant to describe quantitatively solvent screening of interactions between charges on the solute. In combination with solvent polarization a quantum chemical charge model is found superior to an empirical set of charges. Inadequacies of the Lennard-Jones type modelling of non-electrostatic interactions between water molecules are demonstrated.