A theory based on the RPA to calculate the static structure factor for argon-like fluids using LIR equation of state

Abstract

In this work, the random phase approximation theory is applied to generate an expression for the direct correlation function based on the linear isotherm regularity equation of state. We use the hard-core Yukawa potential in the modelling of real fluids, in which the molecular parameters are state-dependent. We use this model to predict the behaviour of the structure factor S(k) in a wide range of states for the argon, krypton and xenon liquids. Finally, we compare our results with the experimental and theoretical data available in the literature. Our calculations are capable of showing the behaviour of S(k) at a wide range of k values with good accuracy, as compared to the experimental data for simple fluids at near and far from their triple points. The Ornstein–Zernike behaviour of S(k) observed at the supercritical region was in satisfactory agreement with experiment.