Calculation of potential relief in large cavity of NaX zeolite for adsorption of methane and cyclohexane

Abstract

The potential relief for adsorption of methane and cyclohexane molecules in a large cavity of NaX zeolite was calculated with the use of the potential function that takes into account the contributions of dispersion, repulsion, and polarization interactions to the total adsorption potential energy of the molecule. The calculations revealed that the deepest potential minimum for a methane molecule lies at the border of a large window, and for a cyclohexane molecule in the center of this window. A different character of the potential reliefs for each of these molecules is attributed to differences in their size and geometry. The energetic mapping was done so as to enable to determine the most probable routes for translation of the molecule in a crystal and at the same time also the potential barriers on these routes. This work is the first stage in numeric modelling of selfdiffusion of hydrocarbons in NaX zeolite.