Liquid metals and plasmas as nucleus-electron mixtures

Abstract

Liquid metals and plasmas are treated as binary mixtures of nuclei and electrons. The thermodynamic potential for the inhomogeneous system caused by fixing one of the nuclei in the mixture is constructed by associating it with a non-interacting ion-electron mixture as a reference system to describe this nucleus-electron mixture. With the use of the hypernetted chain (HNC) approximation, the Kohn-Sham-Mermin formalism based on this leads to a set of integral equations for the correlation functions: this set of integral equations also determines the average nuclear charge of the ion, the electron-ion potential and the electronic bound energy levels in a self-consistent manner, and thus becomes identical to the HNC equation for the ion-electron mixture. The electron-ion direct correlation function determined by these equations is shown to be equivalent to a pseudopotential introduced by Dagens et al. (1975) to take account of the non-linear effects. The conditions for the validity of the various conventional plasma theories, including the problem of estimating the average ionisation, are discussed in view of the present theory.