The nonuniform Wertheim Ornstein-Zernike equation: Density profiles and pair correlation functions of a dimerizing hard sphere near a hard wall

A dimerizing model of hard spheres near a hard wall is studied using the inhomogeneous Wertheim Ornstein-Zernike (WOZ2) equation and the inhomogeneous associative Percus-Yevick (APY2) closure. Dimerization occurs because of the directional associative interactions. A mutually consistent set of density profiles and inhomogeneous pair correlation functions are investigated. Also we obtain the dependence of the association constant on the distance of the fluid particles from the surface. This property is unavailable from singlet integral equations. The application of the WOZ2 equation is an important and promising step in the theory of inhomogeneous chemically associating fluids. This theory allows a lateral ordering of the fluid particles; further, it makes the study phase transformations at the fluid-solid interface, in the presence of chemical association, possible. The combined effects of bulk and surface chemical association can be studied by this method. We expect that a description of wetting phenomena of chemically associating fluids at solid surfaces can be achieved with the WOZ2 equation by using more sophisticated models and more adequate closures.