Modeling multilayer adsorption of interacting polyatomic species on heterogeneous surfaces

► Multilayer adsorption of interacting polyatomics on heterogeneous surfaces. ► A new theoretical isotherm equation is presented in the spirit of the BET model. ► BET analysis is used to estimate the monolayer volume from the new isotherm. ► An underestimated monolayer volume is obtained for non-interacting polyatomics. ► Significant compensation effects appear for attractive interactions and heterogeneity.