对高分子体系进行分子动力学模拟方法的研究

Research on Molecular Dynamic Simulation in Macromolecular System

以单链聚乙烯为例，研究了多种对高分子体系进行分子动力学模拟的方法．结果表明，不同的力场条件可以导致明显不同的结果．在使用OPLS力场的真空条件下．在 100K体系出现了玻璃化现象，在200和 300K条件下体系出现了局部结晶现象，而在 400和 500K体系出现了熔化现象．在给定体系中加入周期性边界和在300K下进行分子动力学模拟，无序和结晶状态都具有一定的稳定性．

Abstract Single polyethylene chain has been used as a model for investigating various molecular dynamic simulation methods that could be useful in the study of macromolecule system. The result of the investigation indicated that different force fields caused obviously different structures of polyethylene. When using OPLS force field under vacuum condition, the phenomena of vitrification were found at 100 K, the phenomena of local crystallization was found at 200 and 300 K, and the phenomena of melting were found at 400 and 500 K. When the periodic box was added to the system, both the disordered state and crystalline state throw out stability to some extent at 300 K in molecular dynamic simulation.