A high-density fluid-perturbation theory based on an inverse 12th-power hard-sphere reference system

Abstract

A variational theory is developed that is accurate at normal liquid densities and densities up to 4 times that of the argon triple point. This theory uses the inverse 12th‐power potential as a reference system. The properties of this reference system are expressed in terms of hard‐sphere packing fractions by using a modified form of hard‐space variational theory. As a result of this ’’bootstrapping,’’ a variational procedure may be followed that employs the inverse 12th‐power system as a reference but uses the hard‐sphere packing fraction as the scaling parameter with which to minimize the Helmholtz free energy.