Perturbation correction for the free energy and structure of simple fluid mixtures

摘要

Adapting an analysis due to Morita and Hiroike and Green which led to the hypernettedhyphen;chain (HNC) integral equation, we obtain an expression for the difference in free energy between a perturbed mixture with potentialsphgr;agr; bgr;equals; phgr;agr; bgr;lpar;0rpar;plus; phgr;agr; bgr;lpar;1rpar;and a reference mixture with potentialsphgr;agr; bgr;lpar;0rpar;a result which is rendered computable by an HNChyphen;type approximation. No further approximations are required to compute the corrected pair distribution functions of the perturbed mixture, but a proposed second approximation yields a particularly simple solution. This work generalizes earlier results on singlehyphen;component fluids.