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采用优化的多体展开势能函数研究面心立方(FCC)晶体铅的动力学和表面性质。在(q00),(qq0)及(qqq)高对称方向,计算声子散射频率与实验曲线良好吻合。Pb(110)表面驰豫严重,其最外层原子向内压缩率达18％,表面7层存在压缩-膨胀交替现象。蒙特卡罗模拟表明,FCC铅在425K开始熔化,模拟结果比纳米铅低约25K。
The kinetic and surface properties of Pb in FCC crystal were investigated by using the optimized multibody expansion function. In (q00), (qq0) and (qqq) high symmetry direction, calculate the phonon scattering frequency and the experimental curve good agreement. The surface of Pb (110) has a serious relaxation. The inward compression rate of the outermost layer of atoms is 18%, and the compression-expansion alternation occurs on the surface of the layer. Monte Carlo simulation shows that FCC lead begins to melt at 425K and the simulation result is about 25K lower than that of nano-lead.