Equation of state for hard-sphere and hard-disc systems

Abstract

We present new equations of state for hard spheres and hard discs, especially for the fluid phase. These equations are subject to a series of constraints: they reproduce exactly all the available calculated values of the virial coefficients and they have a divergence occurring at a density and with a slope as supported by theoretical arguments. Moreover, a small number of adjustable fitting parameters, in fact two, ensures an agreement with ‘experimental’ data available from computer simulations which is as good as possible. The deviation of these data from this new hybrid equation is smaller than from any other equation that we know to be used in this field.