"Two-step" model of molecular diffusion in silicalite

The influence of the particle "memory" on long-range diffusion in the chann el network of silicalite is taken into account by considering pairs of subs equent steps between the channel intersections. It is shown that in this ca se the correlation rule between the principal elements of the diffusion ten sor has to be modified by including an additional term, which takes account of the deviation of molecular propagation from complete randomness. The ob tained relations are discussed in terms of molecular dynamics simulations o f ethane in silicalite. (C) 1999 American Institute of Physics. [S0021-9606 (99)50401-7].