Molecular Dynamics Simulation On Diffusion Properties Of Moleculars In Nano-porous Materials

Nowadays, with the popularity of nano materials in the industrial field, The related properties of molecules confined in nanopores have got more and more attention.Moreover,with the progress of computer science, the method of molecular dynamics simulation is more and more easy to complete. So in this paper, on the basis of previous studies, using the method of molecular dynamics simulation,we discussed the diffusion properties of confined spherical molecules in the nanopores.First of all, Based on the transition state theory, we study the relationship of diffusion coefficient and temperature on ITQ-3 zeolite with special pore structure of Ar.The results show that, The relationship of diffusion coefficient and temperature on the narrow channel of ITQ-3 zeolite of Ar was in accordance with the famous Arrheinius relation.Then, the diffusion behavior ofSF₄ under different loading was discussed. The simulation shows that,with the increase of the molecules, the diffusion coefficient ofSF₄ decreased gradually.In addition, The equilibrium molecular dynamic simulation was carried out to study the diffusion behavior of pure component and the binary components in the ITQ-3 zeolite.The results showed that: For pure Ar,the diffusion coeffieient along the z direction was an increasing function as the loading increase, after reaching a maximum value at some intermediate loading,the diffusion coefficient decreased at higher loading. But in the y direction,the diffusion coefficient decreased momotonically as the loading was increased.Then the diffusion coefficients of binary componentsSF₄ /CF₄ in ITQ-3 zeolize have been studied using molecular dynamic simulation methods. We noted that the diffusion coefficients of binary components retained the trend of their pure component. But4 CF diffused much more slowly in the mixture than as a pure species. Compared to the pureSF₄, the diffusion coefficient ofSF₄ in the mixture was increased. This appeared to be due to the influence of coupling effect between diffusing species.