利用自由能方法的分子动力学模拟,计算了零压下Al的熔化温度。在计算液相自由能的过程中,采用勒纳-琼斯(LJ)液体作为参考系统,同时将计算结果与Mei和Davenport等人的计算结果进行了比较,计算结果表明:1)选用LJ参考系统使液相自由能的计算时间节省一半,并且不影响熔化温度的计算结果;2)采用不同的埋入原子势(EAM)的分子动力学模拟计算得到的熔化温度与实验值都存在偏差,而就金属Al而言,采用Cai等人的EAM势的熔化温度的计算结果比Mei和Davenport及Morris等人采用的势模型的结果略有改善。
In this paper, free energy method is used to calculate the melting poing of A1. We adopt the Lennard-Jones (LJ) liquid as the reference system and compare the calculated results with that of Mei, Davenport, and Morris et al. The calculated results show: (1) Using the LJ reference system, the CPU-time consumed for molecular dynamics simulation is reduced to one half of that of Mei,Davenport,and Morris et al while the results are the same; (2) Errors exist in calculated values of melting point in all molecular dynamics simulations using different versions of empirical embedded-atom-model potentials (EAM). For the metal A1, the calculated result using Cai's EAM potential is improved a little comparing with that using EAM potentials in the simulations of Mei, Davenport, and Morris et al.