利用Gupta势研究COnCu13-n(n=1～12)混合团簇的基态结构和熔化行为

摘要

The ground-state geometries and melting properties of ConCu13-n (n= =0~13) clusters are systematically investigated using the Gupta many-body potential combined with the genetic algorithm and molecular dynamics simulation. Our results show that the ground-state geometry of all these bimetallic clusters are similar to that of the pure Co13(Cu13) cluster, and the central site is prefer to surface ones for replacing the Co atom(s) of the ConCu13-n.(n=1~12) clusters as comparing that of the Cu13, and the surface Co atoms coalesce together. From analyzing the second-order difference energy and the mixing energy, Co1Cu12 and Co7Cu6are found to have relatively high stability and can be considered as the magic number clusters; The melting points of ConCu13-n,(.n = =0~12) clusters increase in general with only one abnormal decline at n = 3, which can be attributed to that the energy gap between the ground state and the first excited state of Co3Cu10 cluster is substantially smaller than that of C02Cu11 cluster.%利用Gupta多体相互作用势结合遗传算法和分子动力学方法模拟研究了ConCu13-n(n==0～13)单质及混合团簇的基态结构和熔化行为,结果表明:ConCu13-n(n=1～12)混合团簇的基态结构均是在单质Co13、Cu13基态二十面体基础之上的畸变,Co原子先占据中心后占据表面,表面上的Co原子总连接在一起,抱团分布;分析二级差分能和混合能发现Co1Cu12、Co7C6具有相对高的稳定性,可视为幻数结构团簇；ConCu13-n(n=1～12)混合团簇的熔点均位于Co13、Cu12单质团簇的熔点之间,且随着Co原子数目的增多总体呈上升趋势,但在n=3时出现反常(熔点降低),这可归因于Co3Cu10的基态与第一激发态之间的能量差远小于Co2Cu11的相应值.