AN MD STUDY OF METHANE DIFFUSION IN ZEOLITES OF STRUCTURE TYPE LTA

Diffusion of methane in zeolites of structure type LTA is simulated by Molecular Dynamics (MD) calculations. Small variations of the Lennard-Jones parameters (determining the window size) and the nature of the considered exchangable cations are found to be of decisive importance for the observed dependences, leading to self-diffusivities which may both increase and decrease with increasing concentration. The different patterns of molecular propagation and their microdynamic origin are visualized by video demonstrations. Taking into account the gradient of the chemical potential as a driving force for the diffusion process the transport-diffusivity is found to increase with increasing concentration.