Molecular dynamics studies of Lennard-Jones liquid mixtures. II. Mass and size dependence in the behavior of one different particle

Abstract

Molecular dynamics calculations have been made for Lennard-Jones liquid mixtures consisting of 107 solvents and one solute. In order to examine the effects of mass and size of solute on the solvent structure around the solute and on the motion of solute, the mass or σ value of the Lennard-Jones potential assigned for a solute was chosen as either twice or half that for solvent, while the ε value for all solutes was assumed to be the same as that for solvent. Thermodynamic quantities, radial distribution functions, velocity autocorrelation functions, and self-diffusion coefficients were obtained. They were compared with those for the corresponding hard sphere system calculated by Alder et al. In some respects, characteristic behaviors of LJ solute were found to be different from those of the hard sphere. In contrast with the case of the hard sphere, the first peak of g12 becomes higher as the size of the solute decreases. The rate of increase in the self-diffusion of LJ solute with decrease in the size of the solute is not so large as that of hard sphere solute.