Molecular Dynamics Simulation of Reorientational Motion of SF6 in Porous Sol-GelGlass

摘要

Molecular dynamics of reorientational motion of SF6 is simulated inside theporous structure representing amorphous sol-gel glass. Simulations are run for different densities of adsorbed SF6. By comparing the theoretical results with available experimental data, it is shown that the model well characterizes molecular properties of sulphur hexafluoride in porous silica. It is found that reorientational relaxation of SF6 inside small pores is dependent on the density of adsorbent. It is concluded that, at elevated pressures, there are less molecules inside the pores than in the same volume on the outside of the sample. The difference in the densities inside the pores and the pure phase may be as high as 30%. Simulations are also run for two different surface potentials, and it is found that reorientational relaxation depends only slightly on potential depth, which can be attributed to the lack of specific interactions between adsorbent and the silica surface. Sol-gel, molecular simulations, SF6.