Dynamic behavior of pairs of atoms in simple liquids

Abstract

The microscopic dynamic behavior of some simple liquids has been investigated by observing the time evolution of the separation between members of pairs of atoms. The distribution function for this process was calculated in molecular-dynamics studies of several states of two model fluids: Lennard-Jones and simulated rubidium. The overall features of the results are described quite well by a simple model in which the distribution of pair separations satisfies Smoluchowski's equation with a potential of mean force. The model uses a nonlinear time scale determined from the single-particle motion.