Adsorption isotherm and other properties of methane in zeolite a from an intermolecular potential derived from ab initio calculations

Abstract

A classical Lennard-Jones potential is derived from a fit to the ab initio energies obtained from an all-electron mixed-basis calculation for methane in zeolite LTA. The potential predicts the heat of adsorption, adsorption isotherm, and self-diffusivity of methane in excellent agreement with experiment. This study suggests, for the first time, that ab initio energies^-in addition to experimental data -can form a good basis for derivation of accurate classical potentials between organic and inorganic elements.