01-17E

Molecular dynamics (MD) simulations are performed for a Lennard-Jones fluid adsorbed in a model silica gel to study the individual particle motions. The mean-square displacement and velocity autocorrelation functions of fluid particles are calculated from the MD simulations at densities corresponded to the gas and liquid phases and for different temperatures, and used to analyze their self-diffusion coefficients. It is shown that the presence of porous media reduces the mobility of fluid particles and hence decreases the self-diffusion coefficient.