%0 Journal Article %A Coppens, M %A Malek, K %C USA %D 2001 %F discovery:1367399 %J Physical Review Letters %N 12 %T Effects of surface roughness on self- and transport diffusion in porous media in the Knudsen regime %U https://discovery.ucl.ac.uk/id/eprint/1367399/ %V 87 %X The effect of surface roughness on Knudsen diffusion in nanoporous media is investigated by means of dynamic Monte Carlo simulations in three-dimensional rough fractal pores. These simulations yield new insight and explain a number of apparent inconsistencies by revealing a striking difference between the roughness dependence of transport diffusion and gradientless (self- or tracer) diffusion. Both analytical and simulation results show a significant roughness dependence of self-diffusion in the Knudsen regime. Transport diffusion, on the other hand, is roughness independent, as the fluxes do not depend on the detailed residence time and molecular trajectories.