摘要
采用分子动力学(MD)方法对纳米单晶氩的扩散性质进行了模拟研究。采用L-J12-6势函数描述氩原子势,半步长的Leap-frog算法求解运动方程,Berendsen热浴法调温,P-R方法调压,在充分弛豫后进行扩散模拟的时间为100 ps,计算得到了10个恒定温度下原子均方位移(MSD)与时间(t)的关系曲线。根据MSD-t曲线特点,分为初始阶段和稳态阶段2个阶段进行数据处理。利用Einstein关系求出了稳态阶段的扩散系数D,由Arrhenius表达式求出了纳米单晶氩的稳态扩散常数D0为0.100 004 509 m2/s、稳态扩散激活能Q为4.848 81×10-21J。
The diffusive properties of single-crystal FCC cubic argon at nano-level is studied by molecular dynamics （MD） using L-J12-6 inter atomic potential. The discrete moving equations are solved with the half stepped Leap-frog method. The adjustments of temperature and pressure for the atom system are done through the Berendsen thermal bathing method and the Parrinello-Rahman （P-R） method respectively. The time of diffusion period is 100 ps after adequate free relaxation and the mean-squared displacement （MSD） of atoms varied with time （t） in ten-fixed temperature in the range of 100 K to 1 500 K. Two-stag method is used here for description of the MSD-t curves rather than the previously proposed one stage method. The first is initial stage and the second is steady stage, but only the steady stage is considered here. The diffusion coefficients （D） for the steady stage can be obtained by using the classical Einstein relationships. The diffusion coefficient D0equal to 0. 100 004 509 m^2/s and the activation energy Q equal to 4. 848 81 ×10^-21J by the Arrhenius expression.
出处
《广西师范大学学报（自然科学版）》
CAS
北大核心
2007年第3期15-18,共4页
Journal of Guangxi Normal University:Natural Science Edition
基金
国家自然科学基金资助项目(50275072)
关键词
纳米单晶氩
扩散
分子动力学模拟
nano-single crystal argon
diffusion
molecular dynamics simulation
