Collect. Czech. Chem. Commun. 2008, 73, 424-438

Some Explicit Results for the Mean Spherical Approximation for Mixtures of Yukawa Fluids

Douglas J. Hendersona,* and Osvaldo H. Scaliseb

a Department of Chemistry and Biochemistry, Brigham Young University, Provo UT 84602-5700, U.S.A.
b Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), UNLP-CONICET-CICPBA, C.C. 565, 1900 La Plata, Argentina


The mean spherical approximation (MSA) is of interest because it produces an integral equation that yields useful analytical results for a number of fluids. One such case is the Yukawa fluid, which is a reasonable model for a simple fluid. The original MSA solution for this fluid, due to Waisman, is analytic but not explicit. Ginoza has simplified this solution. However, Ginoza's result is not quite explicit. Some years ago, Henderson, Blum, and Noworyta obtained explicit results for the thermodynamic functions of a single-component Yukawa fluid that have proven useful. They expanded Ginoza's result in an inverse-temperature expansion. Even when this expansion is truncated at fifth, or even lower, order, this expansion is nearly as accurate as the full solution and provides insight into the form of the higher-order coefficients in this expansion. In this paper Ginoza's implicit result for the case of a rather special mixture of Yukawa fluids is considered. Explicit results are obtained, again using an inverse-temperature expansion. Numerical results are given for the coefficients in this expansion. Some thoughts concerning the generalization of these results to a general mixture of Yukawa fluids are presented.

Keywords: Fluid mixtures; Yukawa potential; Mean spherical approximation; Peturbation expansion; Thermodynamic functions.

References: 14 live references.