Molecular dynamics studies of polar/nonpolar fluid mixtures. II. Mixtures of Stockmayer and polarizable Lennard-Jones fluids

Abstract

The results of canonical ensemble molecular dynamics simulations of mixtures of equisized Stockmayer and polarizable Lennard-Jones fluids are reported. The excess free energy of mixing shows a decrease with increasing polarizability reflecting an increased miscibility. For sufficiently large values of the polarizability, the miscibility gap, observed previously for mixtures of nonpolarizable Lennard-Jones and Stockmayer fluids, is shown to disappear. The results can be explained qualitatively with perturbation theory. The structure and orientational correlation functions of the mixture are discussed. The marked increase in local ordering at low concentrations of the polar component, so prominent in the nonpolarizable case, diminishes with increasing polarizability. As a result the asymmetry of excess properties with respect to composition becomes less pronounced.