EFFECT OF THE RATIO OF RADIUS OF SPHERE TO RADIUS OF CYLINDER ON ADSSORPTION AND SELF-DIFFUSION IN A SPHERE-CYLINDER MICROPORE

The effect of the ratio of the radius of sphere to radius of cylinder, R(s)/R(c) on self-diffusion parallel to the pore walls in a "sphere-cyclinder" model pore has been studied by the molecular dynamics simulation method. The sphere-cylinder micropore consisted of spherical cavities of a few molecular diameters interconnected in a sequence by narrower cylindrical sections (window openings). The ratio of the length of the spherical section to the length of the cylindrical section (along the axial direction of the pore) was A/L = 1.0. The mean reduced temperature and density were 0.4 and 1.49, respectively. The simulation results for R(s)/R(c) = 2.0, 1.54, and 1.18 include local density profiles, self-diffusion coefficient parallel to the pore walls D parallel-to*, mean square displacement (MDS perpendicular-to), and velocity autocorrelation function (VACF perpendicular-to) perpendicular to the pore walls.