中文摘要：

采用分子动力学方法研究了直链烷烃C1-C4在二聚铜-苯-1，3,5-三羧酸酯（Cu—B代）中的扩散机理．首先计算了4种烷烃的自扩散系数，并进一步通过质心分布图与分子轨迹图详细讨论了主、次孔道中各种类型的扩散路径．研究结果表明，不同烷烃在Cu-BTC中表现出的不同或近似的宏观扩散速率，是由微观上受到不同的扩散路径阻力并偏好不同的扩散路径所造成的．这些信息可提高人们对该类材料的认识，并为材料的实际应用以及新材料设计提供理论指导．

英文摘要：

Molecular dynamics simulation was performed to study the diffusion mechanism of n-alkanes C1-C4 in copper （ Ⅱ ） benzene-1, 3,5-tricarboxylate（ Cu-BTC）. The self-diffusivities of n-alkanes were calculated, and the diffusion paths of different types in the main and second channels were discussed by means of center of mass probabilities and trajectories. The simulation results indicate that the diffusion of various n-alkanes in Cu-BTC follows their preferential paths, which have distinct diffusion resistance, leading to the difference in diffusivity. The information obtained provides a better understanding of the diffusion of nalkanes in metal-organic frameworks（MOFs）, as well as to guide the practical applications and future design of new MOFs.