Adsorption and Permeation Events in Molecular Diffusion

Abstract

How many times can a diffusing molecule permeate across a membrane or be adsorbed on a substrate? We employ an encounter-based approach to find the statistics of adsorption or permeation events for molecular diffusion in a general confining medium. Various features of these statistics are illustrated for two practically relevant cases: a flat boundary and a spherical confinement. Some applications of these fundamental results are discussed.

Keywords

• diffusion
• surface reaction
• permeation
• heterogeneous catalysis
• confinement
• geometric complexity