Third virial coefficient and the hard convex body equation of state

Abstract

A modified equation of state of hard convex body fluids is proposed in which the ratio of the third virial coefficients is employed as the second parameter (in addition to the parameter of non-sphericity α); the resulting equation of state yields the dependence of the compressibility factor on density for hard convex body fluids with a considerable variety of shapes within the error estimates of the simulation data. The third virial coefficients of hard convex bodies of one type are expressed in terms of parameters α and τ; the proposed expressions discern between convex bodies of different shapes with the same values of α (e.g. prolate and oblate ellipsoids of revolution) and enable accurate determination of the third virial coefficients in a broad range of non-sphericities.