SELF-DIFFUSION IN A PERIODIC POROUS-MEDIUM WITH INTERFACE ABSORPTION

A matrix eigenvalue problem for the diffusion eigenstates of a periodic porous medium with interface absorption is set up by expanding those eigenstates in terms of the eigenstates of the zero absorption diffusion problem in the same medium. This approach enables us to obtain accurate numerical solutions for many aspects of self-diffusion. We use our approach to evaluate the time-dependent bulk effective or restricted diffusion coefficient of the fluid filled porous medium and other properties that can be measured using NMR techniques, such as the spectrum of spin relaxation times and the spin echo amplitude in the presence of a pulsed magnetic field gradient. © 1995 The American Physical Society.