Equilibrium and nonequilibrium molecular dynamics studies of diffusion in model one-dimensional micropores

Molecular dynamics simulation results are reported for self-diffusion of a hard-sphere fluid in a one-dimensional interconnected spherical cavity-cyli ndrical pore model of zeolites. The mode of transport within the cylindrica l sections of the structure is by single-file diffusion and a scaling relat ionship between the self-diffusivity and the length of the particle files p roposed in recent work is verified using two different nonequilibrium simul ation techniques. It is also shown that strong nonlocal spatial correlation s can exist between the fluid particles in pore systems containing single-f ile channels and these results in con junction with the local spatial depen dence of the transport and equilibrium properties indicate that care needs to be exercised when interpreting experimental measurements of diffusivitie s within zeolitic structures. (C) 2001 Elsevier Science B.V. All rights res erved.