title: Transition from Knudsen to molecular diffusion in activity of absorbing irregular interfaces.
abstract: We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards two-dimensional absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously with density from the Knudsen to the molecular diffusion regime. In the limit where molecular diffusion dominates, we find that this length approaches a constant value of the order of the system size, in agreement with theoretical predictions for Laplacian transport in irregular geometries. Finally, we show that all these features can be qualitatively described in terms of a simple random-walk model of the diffusion process.
authors.affiliation: Departamento de Física, Universidade Federal do Ceará, 60451-970 Fortaleza, Ceará, Brazil.
authors.forename: J S
authors.initials: JS
authors.lastname: Andrade Júnior
authors.forename: H F
authors.initials: HF
authors.lastname: da Silva
authors.forename: M
authors.initials: M
authors.lastname: Baquil
authors.forename: B
authors.initials: B
authors.lastname: Sapoval