Competitive adsorption via the Percus-Yevick approximation

We study the adsorption of an $M$ component mixture of hard sphere particles on to a plane hard surface with adsorption potentials whose Boltzmann factors contain a $\delta $-function. We use exact solutions of the Percus-Yevick approximation for the system to calculate the monolayer densities, the surface excess densities and the variation of density as a function of distance away from the surface. We are able to study the dependence of these quantities on adsorbate particle size and on the strength of the adsorption potential. We discuss several examples, in particular, the adsorption of a mixture of two components which are in dilute solution in a third hard sphere particle fluid.