Dynamic Behaviors in the Diffusion of Adsorbed Molecules in the Micropore of Zeolites as Investigated by Molecular Dynamics and Computer Graphics

Molecular dynamics(MD) method and computer graphics(CG) were applied to understanding the dynamic behaviors of adsorbed molecules with different diameters and weights in various zeolites. The MD method with a simple diatomic potential function was found to be effective for reproducing the structure of zeolites including ZSM-5 and mordenite. It was shown that the three-dimensional pore structure of ZSM-5 was more favorable than the one-dimensional pore structure of mordenite in the diffusion of adsorbed molecules, especially that of a large molecule, in agreement with experimental data. The flexibility of the zeolite framework was also demonstrated to explain the change of zeolite structure with the adsorption of a large molecule.