The diffusion of a mixture of methane and xenon in silicalite was studied using molecular dynamics simulations and pulsed field gradient nuclear magnetic resonance. The ratio of xenon to methane was varied, at a fixed total number of guest molecules, in order to examine the behavior of diffusion in a mixture. High xenon concentrations were found to slow the methane diffusivity in the mixture, while the diffusion of xenon was almost unaffected by high methane concentrations. The reason for the dominance of xenon was its larger local heat of adsorption and its greater mass, as compared to methane, together with the channel size and topology of silicalite. The simulated and experimental data were in very good agreement. The predicted diffusion anisotropy was considered in terms of the correlation rule for diffusion in the interconnected pore system of ZSM-5.

Diffusion of a Mixture of Methane and Xenon in Silicalite: a Molecular Dynamics Study and Pulsed Field Gradient Nuclear Magnetic Resonance Experiments. Jost, S., Bär, N.K., Fritzsche, S., Haberlandt, R., Kärger, J.: Journal of Physical Chemistry B, 1998, 102[33], 6375-81. See also: Molecular Simulation, 2000, 25[1-2], 27-40