Jjm. Beenakker et Sy. Krylov, ONE-DIMENSIONAL SURFACE-DIFFUSION - DENSITY-DEPENDENCE IN A SMOOTH POTENTIAL, The Journal of chemical physics, 107(10), 1997, pp. 4015-4023
A kinetic treatment of the transport of mobile molecules in nanometer
channels is presented, that explores ideas of the Enskog theory of den
se gases combined with molecular relaxation to the substrate. Transpor
t diffusivity is shown to increase strongly with density, as an effect
of effective transfer of mass in the nonlocal intermolecular collisio
ns. The effect is partially compensated by the additional collisional
relaxation, that would be absent in the truly one-dimensional system o
f hard rods, but is shown to occur in the realistic cases of quasi-one
-dimensional channels and/or ''soft'' particles. A resulting behavior
of diffusivity as a function of density close to 1/(1-theta), where th
eta is the degree of occupancy, is expected. This suggests an explanat
ion for the puzzling universal behavior observed earlier in zeolites.
(C) 1997 American Institute of Physics.