title: Mass transfer in a nanoscale material enhanced by an opposing flux.
abstract: Diffusion is known to be quantified by measuring the rate of molecular fluxes in the direction of falling concentration. In contrast with intuition, considering methanol diffusion in a novel type of nanoporous material (MOF ZIF-8), this rate has now been found to be enhanced rather than slowed down by an opposing flux of labeled molecules. In terms of the key quantities of random particle movement, this result means that the self-diffusivity exceeds the transport diffusivity. It is rationalized by considering the strong intermolecular interaction and the dominating role of intercage hopping in mass transfer in the systems under study.
authors.affiliation: Leipzig University, Faculty of Physics and Geosciences, Linnéstrasse 5, D-04103 Leipzig, Germany. chmelik@physik.uni-leipzig.de
authors.forename: Christian
authors.initials: C
authors.lastname: Chmelik
authors.forename: Helge
authors.initials: H
authors.lastname: Bux
authors.forename: Jürgen
authors.initials: J
authors.lastname: Caro
authors.forename: Lars
authors.initials: L
authors.lastname: Heinke
authors.forename: Florian
authors.initials: F
authors.lastname: Hibbe
authors.forename: Tobias
authors.initials: T
authors.lastname: Titze
authors.forename: Jörg
authors.initials: J
authors.lastname: Kärger