Molecular dynamics study of liquid–vapor coexistence curves and supercritical fluids

Abstract

We calculate the liquid–vapor coexistence curves for several interatomic potentials by the NpT plus test particle method. We also investigate the structure of supercritical fluids in the process of expansion. We find several universal properties irrespective of these potential types: (1) The law of rectilinear diameter is fulfilled. (2) The supercritical fluids expand inhomogeneously. (3) The coexistence curves scaled by the critical constants almost coincide with one another. As for a potential dependent property, we explain the behavior of the critical point systematically by using a quantity which characterizes the feature of attractive force.