Principles of the adsorption theory of large molecules on nonuniform surfaces

A new theory of adsorption of large molecules blocking more than one adsorption center on a nonuniform surface, taking into account lateral adsorbate-adsorbate interactions, was proposed. The cluster approach was used to obtain equations of adsorption isotherms. The lateral interactions are taken into account in the quasi-chemical approximation preserving effects of direct correlations. Ways of simplified description of the multicentered adsorption on nonuniform surfaces were considered: a model of isolated contacts for nonspherical molecules and a quasi-one-centered model for spherically symmetric molecules adsorbed on amorphous surfaces. The resulting equations cover all equations previously considered in the literature for the adsorption of large molecules on uniform and nonuniform surfaces.