不同势下铱团簇结构和熔化行为的分子动力学模拟

采用分子动力学方法及淬火技术，结合Gupta势和Sutton-Chen势，模拟研究了包含13，14，55，56，147及148个原子数的铱团簇的熔化行为. 结果表明，Gupta势和Sutton-Chen势对所研究的Ir团簇的基态几何结构和熔化行为给出了基本一致的描述：两种不同势给出了完全相同的基态几何结构；两种势给出的Ir团簇熔点及预熔化区间随团簇尺寸的变化关系基本一致；对于小Ir_n团簇（n=13,14）两类势均表现出比热峰值相对于均方根键长涨落饱和值滞后的现象. 但是关键词：铱团簇分子动力学Gupta势和Sutton-Chen势熔化

Molecular dynamics simulation of structures and melting behaviours of iridium clusters with different potentials

The molecular dynamics method and quenching technique combined with the Gupta potential and the Sutton-Chen potential are used to study the melting properties of Ir_n （n=13, 14, 55, 56, 147 and 148） clusters. Our results show that the structures and melting behaviors of these clusters described by both potentials are generally in agreement with each other: the same ground state geometrical structure and the same trend of variation of the melting point and the pre-melting interval with cluster size are obtained for both potentials, and for the small Ir_n （n=13,14） clusters, the peak value of heat capacity is delayed from the saturation value of Lindemann index. While, for each of these iridium clusters, the melting point from the Gupta potential is higher than that from the Sutton-Chen potential, and we attribute the main reason to the higher energy gaps between the ground state and the first excited state of these iridium clusters from the Gupta potential than those from the Sutton-Chen potential.