The diffusion of methane in partially de-aluminated zeolite Na A was studied by molecular dynamics using a vibrating framework model for various loadings and aluminium contents. The methane molecules were represented by Lennard-Jones particles. The computed diffusion coefficients increased with increasing loading and decreasing aluminium content, in agreement with experiment.

A Molecular Dynamics Study of Diffusion of Methane in Partially De-Aluminated Zeolite Nacaa. Demontis, P., Suffritti, G.B.: Molecular Physics, 1997, 91[4], 669-79