Summary: Correlation effects in molecular diffusion in zeolites at infinite dilution
Fabien Joussea)
Laboratoire de Physico-Chimie Informatique, Institute for Studies in Interface Science, Faculte´s
Universitaires Notre-Dame de la Paix, B­5000 Namur, Belgium and Department of Chemistry,
University of Massachusetts, Amherst, Massachusetts 01003
Scott M. Auerbach
Department of Chemistry and Department of Chemical Engineering, University of Massachusetts, Amherst,
Massachusetts 01003
Daniel P. Vercauteren
Laboratoire de Physico-Chimie Informatique, Institute for Studies in Interface Science,
Faculte´s Universitaires Notre-Dame de la Paix, B­5000 Namur, Belgium
Received 6 August 1999; accepted 12 October 1999
Molecular diffusion in zeolites is often resumed to a random walk between specific adsorption sites
within the channels and cavities of the materials. Several types of correlations between the steps of
the walk come to precise this assumption: kinetic correlations due to the incomplete relaxation of the
molecule in its final site, vacancy correlations arising at high loading because molecules are
blocking each other, and geometrical correlations because zeolite channels and cages can boast
nonsymmetric sites. The first and last correlation effects can be observed at infinite dilution. In this
article we present a way of calculating an exact diffusion coefficient at infinite dilution as a function
of the microscopic rate constants, taking into account both geometric and kinetic correlation effects.

Source: Auerbach, Scott M. - Department of Chemistry, University of Massachusetts at Amherst

Collections: Chemistry