控温方式对甲烷自扩散和局部结构影响 的分子动力学模拟

运用分子动力学模拟方法,通过设置两种控温方式(Andersen和Berendsen),研究了甲烷在较宽温度和压力范围的分子自扩散系数和配位数.结果表明,采用Andersen控温方式得到的甲烷自扩散系数与文献实验值相差甚远,而以Berendsen控温方式得到的甲烷自扩散系数与文献实验值较吻合,并且两种控温方式得到的甲烷平均配位数相差较小.因此,应采用Berendsen控温方式对甲烷的自扩散行为进行分子动力学模拟研究.

Molecular Dynamics Simulation of the Influence of Thermostat Algorithm on Self-diffusion and Local Structure of Methane

Self-diffusion coefficients and coordination numbers of methane over wide range of temperature and pressure were studied by molecular dynamics simulation under Andersen and Berendsen thermostat algorithm. The result shows that the simulated self-diffusion coefficient of methane under Andersen thermostat algorithm is far from the experimental value in literature, while the simulated self-diffusion coefficient of methane under Berendsen thermostat algorithm is consistent with the experimental value in literature. On the other hand, the difference in the average coordination numbers of methane between Andersen and Berendsen thermostat algorithm is small. Therefore, Berendsen thermostat algorithm should be used to study the self-diffusion behaviore of methane by molecular dynamics simulation.