Al_(196)团簇结构及熔化行为的分子动力学模拟

Molecular dynamical simulations of the structural and melting properties of Al_(196)cluster

运用分子动力学方法结合退火及淬火技术,采用半经验的Gupta原子间多体势,系统研究了Al_(196)团簇的熔化特性.模拟结果表明:从不同的初始结构出发得到的熔化行为明显不同.从较低能量稳定结构出发,会出现明显的比热呈现双峰的熔化行为;而从基态或接近于基态的低能稳定结构出发.则呈现出比热显示单峰的熔化现象.通过分析不同温度点上团簇淬火结构的势能分布图给出了Al_(196)团簇的不同(比热出现双峰或单峰)熔化行为的成因.

Based on the Gupta-type semi-empirical inter-atomic many-body potential, the melting behav- iors of the A1~96 cluster are systematically studied by using the molecular dynamics method combined with the annealing and quenching techniques. Our simulation results show that from different initial structures one can observe quite different melting behaviors. From a relatively low-energy stable geome- try,two peaks occur clearly in the heat capacity curve~ but only one peak dominates the heat capacity curve if starting from the ground-state or its closer low energy structures. Reasons of the different melt- ing properties of the A1~96 cluster are explored by analyzing the energy distributions of the simulated quenching structures of Al196 at different temperatures.