Multisite Occupancy Adsorption: Comparative Study of New Different Analytical Approaches

Abstract

The adsorption of dimers on honeycomb, square, and triangular lattices is studied by combining theoretical modeling and Monte Carlo simulations in canonical and grand canonical ensembles. The adsorption thermodynamics is analyzed through the adsorption isotherm and the configurational entropy of the adsorbate. Three theoretical models to study dimers' adsorption on two-dimensional lattices have been proposed: (i) the first, which we called occupation balance, is based on the expansion of the reciprocal of the fugacity; (ii) the second is an extension to 2-D of the exact partition function obtained in 1-D; and (iii) the third is a virial expansion. Results are compared with corresponding ones from the Flory's approximation and from the Monte Carlo simulations. Significant quantitative differences are shown and discussed. In all cases, the occupation balance appears as the more accurate model.