Intermolecular potential functions for adsorption in zeolites: State of the art and effective models

In the simulation of physical adsorption, the adsorbate-adsorbent potential function plays a central role. Much labour is involved in obtaining a potential function which takes into account two-body and three-body dispersion terms in place of a more empirical effective potential, and it is important to enquire whether effective potentials can furnish an acceptable solution to the problem. Here we review the construction of a more elaborate potential function for the interaction of non-polar probes with silicalite and with AlPO4-5, and analyze the contributions which arise from the different terms. The possibility of employing effective potentials based on the summation of 12-6 or 6-exp functions is examined, and it is concluded that no guarantee can be offered for the success of the simplified procedure.