THERMODYNAMICS OF THE ASSOCIATIVE MEAN SPHERICAL APPROXIMATION FOR THE FLUID OF DIMERIZING PARTICLES

Analytical expressions for the thermodynamic properties of the n-compo nent mixture of dimerizing hard spheres with a long-range potential ar e derived within the associative mean spherical approximation. The der ivation is based on the extension of the Hoye-Stell scheme [J. Chem. P hys. 67, 439 (1977)] in the framework of the Wertheim's two-density fo rmalism for associating fluids and the exponential approximation recen tly suggested by Bernard and Blum [J. Chem. Phys. 104, 4746 (1996)]. I n 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 th e corresponding results obtained earlier by the other authors. Closed form expressions for the Helmholtz free energy, chemical potential, an d pressure of the complete association version of the electrolyte rest ricted primitive model with the additional sticky-point attraction are derived. (C) 1998 American institute of Physics.