几何结构对Na8团簇熔化过程的影响

运用距离相关紧密结合的分子动力学模型,对金属原子团簇Na8的两种不同的异构体进行了数值模拟.根据零温下基态结构中不同原子到质心的不同距离,把Na8的两种异构体分为多个子系统.分别提取各个子系统在不同温度下的围绕质心的径向分布、无单位键长涨落、平均位移、扩散系数,发现尽管两个异构体的基态能量很接近,但他们的稳定性、熔化过程的热力学性质等有着很大的差别,这也反映了它们在几何结构上的差别.

Effect of geometry structure on Melting process of Na8 cluster

Within the framework of distance dependent tight-binding molecular dynamics (DDTB-MD) using adiabatic approximation,the two different kinds of Na8 isomers are simulated.According to different distances of different atoms from center of mass in ground structure for zero temperature,these two kinds of Na8 isomers are classified many sub-systems.In the case of different temperature,for different sub-systems,the radial distribution around the center of mass,fluctuation of bond length,mean displacement are calculated respectively.It is found that although the ground state energy of the two kinds of isomers are similar,there instability and thermodynamical characters in the melting process are quite different,which further suggests their distinctions in geometry structure.