Anomalous Diffusion in Random Pores

Molecular dynamics simulations are performed for binary liquids confined in the pores of Vycor glass. The individual molecular motions are studied by computing F-s, the self-part of the concentration fluctuation autocorrelation function. The results for F-s(q,t) show that the diffusion is anomalous as its relaxation rate does not follow the usual q(2) dependence on the probing wave vector q. This is explained as a confining effect of the glass walls. (C) 1998 American Institute of Physics