Thermodynamics of the associative mean spherical approximation for the fluid of dimerizing particles

Abstract

Analytical expressions for the thermodynamic properties of the n-component mixture of dimerizing hard spheres with a long-range potential are derived within the associative mean spherical approximation. The derivation is based on the extension of the Ho/ye–Stell scheme [J. Chem. Phys. 67, 439 (1977)] in the framework of the Wertheim’s two-density formalism for associating fluids and the exponential approximation recently suggested by Bernard and Blum [J. Chem. Phys. 104, 4746 (1996)]. In the complete association limit, in which the two-density associative mean spherical approximation reduces to Chandler–Silbey–Ladanyi mean spherical approximation, results of the present study coincide with the corresponding results obtained earlier by the other authors. Closed form expressions for the Helmholtz free energy, chemical potential, and pressure of the complete association version of the electrolyte restricted primitive model with the additional sticky-point attraction are derived.