The average correlation function of hard convex bodies and the hard body equation of state

Abstract

A simple approximation for the average correlation function of hard convex bodies is proposed based on the knowledge of the total correlation function of equivalent hard spheres. The proposed relationship yields very good predictions for the third and fourth virial coefficients of the prolate and oblate hard spherocylinders, and for the contact values of the average correlation functions of prolate spherocylinders and of their mixtures with hard spheres. The approximation reproduces fairly well the dependence of the average correlation functions on distance. The two parameter equation of state formulated on its basis predicts the compressibility factor of hard bodies of different shapes with fair accuracy and appears to be more general than the relationships available up to date.