title: Assessing guest diffusivities in porous hosts from transient concentration profiles.
abstract: Using the short-chain-length alkanes from ethane to n-butane as guest molecules, transient concentration profiles during uptake or release (via interference microscopy) and tracer exchange (via IR microimaging) in Zn(tbip), a particularly stable representative of a novel family of nanoporous materials (the metal organic frameworks), were recorded. Analyzing the spatiotemporal dependence of the profiles provides immediate access to the transport diffusivities and self-diffusivities, yielding a data basis of unprecedented reliability for mass transfer in nanoporous materials. As a particular feature of the system, self- and transport diffusivities may be combined to estimate the rate of mutual passages of the guest molecules in the chains of pore segments, thus quantifying departure from a genuine single-file system.
authors.affiliation: Faculty of Physics and Geosciences, Department of Interface Physics, University of Leipzig, Linnéstrasse 5, 04103 Leipzig, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Heinke
authors.forename: Despina
authors.initials: D
authors.lastname: Tzoulaki
authors.forename: Christian
authors.initials: C
authors.lastname: Chmelik
authors.forename: Florian
authors.initials: F
authors.lastname: Hibbe
authors.forename: Jasper M
authors.initials: JM
authors.lastname: van Baten
authors.forename: Hyuna
authors.initials: H
authors.lastname: Lim
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Rajamani
authors.initials: R
authors.lastname: Krishna
authors.forename: Jörg
authors.initials: J
authors.lastname: Kärger