Abstract
When large adsorbates diffuse in the pores of zeolites and molecular sieves, they can undergo single-file diffusion. The mean-square displacement of particles during single-file diffusion, 〈[Formula Presented](t)〉, is proportional to [Formula Presented]. By contrast, in the absence of other particles, an isolated adsorbate will perform normal diffusion with a tracer diffusion coefficient [Formula Presented]. An important goal of theoretical treatments of single-file diffusion is to relate [Formula Presented] and the single-file mobility, F=〈[Formula Presented](t)〉/[Formula Presented]. One physical feature that is ubiquitous in activated diffusion in periodic potentials, such as the diffusion of adsorbates in zeolites, is the appearance at sufficiently high temperatures of correlated flights that pass through multiple binding sites. We show that when isolated particles can perform multisite flights, the expression usually used to relate [Formula Presented] and F is not exact, and we investigate methods that can lead to more accurate expressions. We discuss how the existence of long flights affects equilibrium adsorbate structures and comment on the implications of our results for the interpretation of experimental measurements of single-file diffusion.
Original language | English (US) |
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Pages (from-to) | 7753-7756 |
Number of pages | 4 |
Journal | Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics |
Volume | 55 |
Issue number | 6 |
DOIs | |
State | Published - Jan 1 1997 |
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Statistics and Probability
- Condensed Matter Physics