分子动力学结合不同势研究Ir团簇熔化性质

Study of Melting Properties of Iridium Clusters by Using Molecular Dynamics with Different Potentials

采用Gupta势和Sutton-Chen势运用分子动力学方法研究了Irn(n=13,14,55,56,147)团簇的熔化行为.结果表明:对于所研究尺寸团簇,两种不同势给出了完全相同的基态几何结构.两种势给出的铱团簇熔点随团簇尺寸的变化关系基本一致、预熔化温度区间随团簇尺寸的变化关系完全一致.对于小团簇(Ir13、Ir14)两类势均表现出比热峰值相对于均方根键长涨落滞后的现象.

The melting properties of Irn（n=13,44,55,56,147）clusters are studied by using molecular dynamics simulations with two different potentials ： the Gupta potential and the Sutton-Chen potential. Same ground state geometrical structures are obtained for both potentials. Variations of melting temperature with cluster size of the two different potentials are consistent with each other, and variations of pre-melting temperature interval with cluster size are exactly the same for both potentials. For the small clusters （Ir13, Ir14）, both potentials show that the appearance of the maximum of the heat capacity curve is delayed from the rapid change of the Lindemann index.