On the fluid phase behaviour of fluid binary mixtures using the Yukawa fluid molecular model

By expanding Ginoza’s mean spherical approximation (MSA) results in an inverse-temperature expansion, Henderson et al. obtained explicit results for the thermodynamic functions of a pure Yukawa fluid. We have recently published explicit results for the coefficients in an inverse-temperature expansion of the thermodynamic functions for the MSA for mixtures of Yukawa fluids. Attention is drawn to the fact that the MSA in the Ginoza formulation, does not always yield a convergent solution. The expansion used in this paper will always yield a result. In this work we present our investigations of the fluid phase diagram of Yukawa binary mixtures by considering an expansion of the MSA Helmholtz free energy up to the fifth order of the inverse-temperature expansion. The calculated fluid phase diagrams for Yukawa binary mixtures are similar to those of real mixtures.