分子动力学模拟研究钯金属团簇的熔化行为

用分子动力学方法，模拟了三种具有壳对称构型，含309个原子的钯金属团簇的熔化行为。钯原子间作用势采用Sutton-Chen多体作用势能。三种壳对称构型分别为正八面体（Cubooctahedron），正十面体（Decahedron）和正二十面体（Icosahedron）。通过对升温过程中的热力学性质的分析，得到了钯金属团簇的熔点。不同构型钯金属团簇的熔点有细微差别，并且都远低于块状钯金属的熔点。进一步分析三种钯金属团簇升温过程中的结构和动力学性质，在分子水平上讨论了构型对熔化行为的影响。

Molecular dynamics simulation of the melting behavior of shell-symmetric palladium clusters

The melting behaviour of bulk palladium(Pd),and three isolated shell-symmetric 309 atom configured Pd clusters,with cubooctahedral,decahedral and icosahedral geometries,have been investigated by molecular dynamics(MD) simulations,using the Sutton-Chen many-body potential(SC) for the interaction between the Pd atoms.The thermal,structural and dynamic properties were calculated for bulk Pd and the Pd clusters during the heating process.From the thermal property analysis,it was found that the Pd clusters melt at temperatures much lower than the melting point of bulk Pd,with a little difference between the three Pd clusters.From the pair correlation function analysis,it was found that the shell segregation vanishes after melting of the Pd clusters.Furthermore,dynamic evidence was found for the surface pre-melting of the Pd clusters.