Modeling multilayer adsorption of interacting polyatomic species on heterogeneous surfaces

In the present work, a generalized lattice-gas model to study multilayer adsorption of interacting polyatomic species on heterogeneous surfaces is introduced. Using an approximation in the spirit of the well-known Brunauer-Emmet-Teller (BET) model, a new theoretical isotherm is obtained in one- and two-dimensional lattices and compared with Monte Carlo simulation. In addition, the BET approach is used to analyze these isotherms and to estimate the monolayer volume. In all cases, the application of the BET equation leads to an underestimate of the true monolayer capacity. However, significant compensation effects were observed for heterogeneous surfaces and attractive lateral interactions.