摘要:
采用分子动力学方法,对短链烷烃在柔性和刚性具有相似拓扑结构的金属有机骨架材料（isoreticular metal-organic frameworks,IRMOFs）中的分子扩散进行了研究.结果表明,分子在柔性骨架中的自扩散系数大于在刚性骨架中的自扩散系数,在柔性骨架中的活化能小于在刚性骨架中的活化能.骨架的柔性对自扩散系数的影响随着温度的升高而增加,随着扩散分子数目以及扩散分子链长的增长而降低.因此,在利用分子模拟方法研究烷烃在金属-有机骨架材料中的扩散行为时,尤其对于较高温度以及较短的烷烃分子,使用柔性力场可以得到更合理的结果.
Abstract:
Molecular dynamics simulations is performed to study the diffusion of several short alkanes in a flexible and rigid metal-organic framework, IRMOF-1. The results show that the self-diffusivities of alkanes in the flexible framework are larger than in a rigid framework and the activation energies in the flexible framework are less than in the rigid framework. The effect of framework flexibility on the self-diffusiviy increases with temperature inereasing and loading or chain length decreasing. Therefore, in the study of the diffusion behavior of alkanes in the metal-organic framework materials using molecular simulation method, especially for the case of the high temperature and shorter alkane molecules, flexible force field may give more reasonable results.
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