MOLECULAR DYNAMICS SIMULATION STUDIES OF THE DENSITY AND TEMPERATURE CYLINDRICAL MICROPORE

We report Molecular Dynamics calculations of radial density profiles and self-diffusion coefficients of Lennard-Jones fluids in a cylindrical pore of radius 2 sigma, for a wide range of temperatures and densities. At n(p)sigma(3) = 0.825 the self-diffusion coefficient parallel to the pore walls D-parallel to(center dot); fo llows a monotonic ( nearly linear) increase with kT/epsilon and is very similar to that of the bulk self-diffusion coefficient D-b(center dot) At n(p)sigma(3) = 0.4 and kT/epsilon <= 1.0 the curve of D-parallel to(center dot) vs. kT/epsilon shows a distinct inflection in the region 0.7 <= kT/epsilon <= 0.9 and values of D-parallel to(center dot) are much less than D-b(center dot) decreasing to near solid state values at very low temperatures. At the highest temperature studied, kT/epsilon = 2.98, D-parallel to(center dot) is almost inversely proportional to density and in a fairly close agreement with that of D-b(center dot). At KT/epsilon = 0.49, D-parallel to(center dot) is much smaller than D-b(center dot), The motion of adsorbate particles normal to the walls is also discussed.