Multilayer Adsorption of Interacting Polyatomics on Heterogeneous   Surfaces
  In the present work we introduce a generalized lattice-gas model to study the multilayer adsorption of interacting polyatomics on heterogeneous surfaces. 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, we use the BET approach to analyze these isotherms and to estimate the monolayer volume. In all cases, we found that the use 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. 
Fabricio Orlando S\'anchez-Varretti, Guillermo Daniel Garc\'ia,   Antonio Jos\'e Ramirez-Pastor
cond-mat.stat-mech