A diffusion model for the fluids confined in micropores

The self-diffusion coefficients were calculated by molecular dynamics simulations and the effects of pore width, temperature, and fluid density on diffusion behavior of simple fluid argon and polar fluid water confined in micropores were analyzed and studied. A mathematical model describing diffusion behavior of fluids confined in micropores was proposed from the theories of molecular dynamics and molecular kinematics, and validated on the basis of the simulation results at various conditions. The model indicates that the diffusion coefficient is proportional to the square root of the pore width and to the temperature divided by the density squared. It is applicable to either liquid or gas states and only two parameters are required. (C) 2005 American Institute of Physics.