Correlations in the Ar-Kr liquid mixture

Abstract

The Ar-Kr mixture at p = 12 MPa and T = 135 K was simulated by Molecular Dynamics (MD). An analysis was carried out of the concentration dependence of radial distribution functions (RDF), the potential of the mean force, the mean square displacement (MSD), the velocity autocorrelation function (VAF) and self-diffusion coefficients (SDC). Emphasis is put on the physical interpretation of the observed dependence. A dual approach which takes into consideration both the dynamical picture which is based on forces, and the collisional picture which is based on the conservation of linear momentum, yields a deep insight into the nature of the physical processes studied.The potential of the mean force yields a prediction of the shifts in the second RDF peak in accordance with those observed in the literature. A second order series expansion of VAF at short times was carried out. The resulting coefficients give an estimate of the mean effective acceleration of particles as a function of concentration.