Statistical mechanics of regular mixtures

Abstract

The approximate combinatory method devised by Fowler and Guggenheim for the treatment of superlattices is here used to derive the quasi-chemical formulae for a regular mixture regarded as a system of nearly independent pairs of neighbouring sites. The method is then applied to the same mixture regarded as a system of nearly independent triplets or quadruplets of neighbouring sites on a close-packed lattice. Quantitative results for the equilibrium properties obtained by the three approximations differ from one another only very slightly.