CONICET | Buscador de Institutos y Recursos Humanos

Mobile adsorption on heterogeneous surfaces at low coverage is modeled via a gas-solid virial expansion, following the ideas of the Generalized Gaussian Model to incorporate energetic topography effects. Adsorbate molecules interact among them via Lennard-Jones interactions. Model predictions are compared to Monte Carlo simulations of adsorption on heterogeneous solids obtained by doping a pure crystalline solid with different concentrations of impurities. Energetic topography effects are shown to be important and they are correctly predicted by the model at low coverage. Adsorption of particles with nearest-neighbor attractive and repulsive interactions is studied through Monte Carlo simulation on bivariate surfaces characterized by patches of weak and strong adsorbing sites of size l. Patches are considered to have either a square or a strip geometry and they can be either arranged in a deterministic ordered structure or in a random way. Quantities are identified which scale obeying power laws as a function of the scale length l. Consequences of this finding are discussed for the determination of the energetic topography of the surface from adsorption measurements.