中介尺度Au纳米团簇熔化的分子动力学模拟

采用分子动力学模拟技术，研究了原子个数为16～8628的 Au纳米团簇的熔化过程.采用 Johnson的EAM (embedded atom method) 模型,模拟结果表明，金属纳米团簇存在一中介尺度区域.对Au纳米团簇而言，当原子个数N >456时，团簇的热力学性质与团簇尺寸呈线性关系，熔化首先从表面开始，逐步向中心区域推进，且满足Tmb－Tmc(N)＝aN(－1/3)的关系.另外，计算了中介区域的团簇的尺寸、熔化温度、表面能、熵、焓等热力学量以及均方根位移（RMSD）等动力学量，为研究纳米团簇提供定量数据.

Melting of Au Nanoclusters by Molecular Dynamics Simulation

We present a detailed molecular dynamics study of the melting of Au nanoclusters with up to 8628 atoms within the framework of the embedded atom method(EAM). The simulation indicates that there exists a mesoscale nanocrystal regime in metal nanoclusters. The predicted thermodynamics properties for Au nanoclusters above 456 atoms show a linear dependence on the cluster size, whereas the melting begins from the surface of the clusters with a melting point at -(N)=aN(-1/3). In addition, the cluster size, surface energy as well as the average root mean square displacement (RMSD) of the clusters in the intermediate regime have been investigated.