The reaction field method in molecular dynamics simulations of point-polarizable water models

Abstract

Models of liquid water have been studied that, while conceptually simple, incorporate the contributions from both molecular polarizability and long-range interactions explicitly. The models use nuclei-centred polarizable point-dipoles in conjunction with the reaction field method, assuming a rigid molecular geometry. In a molecular dynamics implementation of such models, the presence of the reaction field term gives rise to specific additional torques; these are most readily accounted for by a force redistribution method, thus allowing for the use of standard constraint dynamics. It is found that determination of the ‘true’ induced polarization via iteration does not necessarily involve a large computational overhead and hence constitutes a viable alternative to the extended Lagrangian methods that imply internal molecular fluctuations. As an example of this class of water models, the parametrization of simple three- and four-site models with an oxygen-centred isotropic polarizability term has been consid...