Thermodynamic and structural properties of a sticky hard-sphere heteronuclear dimer fluid

The thermodynamic and structural properties of a sticky hard-sphere heteronuclear dimer fluid are studied using the multidensity Ornstein-Zernike integral equation theory. In this heteronuclear dimer fluid, each molecule consists of two sticky hard-sphere beads with identical diameters but interact with different strengths of stickiness. In this theoretical formalism, a monodisperse system of the heteronuclear sticky dimer is modeled as an equal molar binary mixture of associating sticky hard spheres (with different sticky strengths) in the complete association limit. A general analytical solution to the model was obtained within the Percus-Yevick and polymer Percus-Yevick approximations for any degree of association including the complete association limit. Explicit analytical expressions for the contact values of correlation functions are obtained. Furthermore, correlation functions beyond the hard-core region are calculated. The Helmholtz energy, Gibbs energy, and pressure of the heteronuclear dimer are obtained via the energy route. In addition, the critical temperature, critical density, and phase coexistence of the fluid are also computed. (C) 2002 American Institute of Physics.