Results of Percus-Yevick approximation for a binary mixture of hard spheres with nonadditive diameters; <i>R</i>11=<i>R</i>22=0, <i>R</i>12 &amp;gt; 0

Abstract

We investigate the properties of binary mixtures of hard sphere fluids with nonadditive diameters: Calling Rij the distance of closest approach between particles of species i and j we assume R12=½ (R11 + R22)+α with α≠0. We find the exact solution of the Percus-Yevick integral equation for this system in both one and three dimensions when R11 = R22 = 0, α &amp;gt; 0 (Widom-Rowlinson model). The solution of the PY equation for the Widom-Rowlinson model exhibits a phase transition (corresponding to a separation of the components) in three but not in one dimension. This is in agreement with the true behavior of this system. The critical indices in three dimensions are classical.