A thermodynamically consistent analytical approximation for the structure factor of one-component classical plasma

Abstract

A simple and accurate analytical approximation for the structure factor of the one-component classical plasma (OCP) is proposed, based on the work of Chaturvedi and co-workers (1981). The exact solution of the hard-core OCP model in the generalised mean-spherical approximation is used to construct the Pade approximants for the packing fraction eta and Yukawa tail parameter lambda from the conditions of thermodynamical consistency of the OCP structure factor and recent Monte Carlo simulations. The model provides the OCP structure factor in closed analytical form which is in a very good agreement with the Monte Carlo simulations of Galam and Hansen (1976) when the OCP coupling constant is in the region Gamma >20. The thermodynamic properties of liquid sodium near the melting point have been calculated with the OCP as a reference system in the variational method (called the OCPV method) and compared with the results of the hard-sphere variational method and the very accurate Weeks-Chandler-Andersen thermodynamic perturbation theory. The accuracy of the OCPV method appears to be sufficiently high for calculations of liquid metal properties under pressure.