TY - JOUR JF - Physical Review Letters VL - 87 ID - discovery1367399 UR - http://dx.doi.org/10.1103/PhysRevLett.87.125501 Y1 - 2001/09// TI - Effects of surface roughness on self- and transport diffusion in porous media in the Knudsen regime CY - USA IS - 12 AV - public A1 - Coppens, M A1 - Malek, K N2 - 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. ER -