MOLECULAR-DYNAMICS INVESTIGATION OF THE DIFFUSION OF METHANE IN A CUBIC SYMMETRY ZEOLITE OF TYPE-ZK4

Extensive molecular dynamics simulations of methane diffusion in a cubic-type zeolite ZK4 have been performed by using a model including the vibrations of the silicate framework. In order to understand the role of the lattice dynamics in assisting the diffusive motion of the sorbed molecules we studied the same system also in the rigid framework approximation. Even more evidently than in the case of zeolite structures where the micropores are essentially cylindrical, the framework oscillations are confirmed to be an essential factor in determining the magnitude of the intracrystalline diffusion coefficient.