On the characterization of heterogeneous surfaces through the dual site–bond model

The statistical description of the energetic topography of heterogeneous solid surfaces and the problem of its determination from experimental results are discussed in terms of the dual site–bond model. The effects of the topography on surface processes such as adsorption and thermal desorption, as predicted by the model, are obtained through Monte Carlo simulations. It is shown that adsorbate–adsorbate interactions and adsorptive energy topography may compete with each other in such a way as to produce an indetermination in the characterization from experimental adsorption isotherms and that such an indetermination can be overcome through the analysis of thermal desorption experiments.