ConCu（38-n）（n=0-38）团簇基态结构和熔化行为  

The ground-state geometries and melting behaviors ofConCu（38-n） （n=0- 38） clusters

作　　者：文静[1] 李春丽[1] 孙学贵[1] 段海明[1] 

机构地区：[1]新疆大学物理科学与技术学院,乌鲁木齐830046

出　　处：《原子与分子物理学报》2013年第5期749-757,共9页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(10864005;11164029);新疆维吾尔自治区自然科学基金(2011211A008)

摘　　要：基于半经验的Gupta多体势采用遗传算法和分子动力学方法并结合模拟淬火技术，系统研究了ConCu（38-n）（n=0-38）团簇的基态结构与熔化行为．结果表明：除Co7Cu31团簇基态为类IA结构外，其它ConCu（38-n）混合团簇的基态结构均是在单质Cuss（Co38）的Oh基态结构基础上的畸变；对于混合团簇的基态结构，随Co原子增加均表现出Co原子先占中心后占表面的特征；通过分析基态团簇二阶差分能和混合能表明Co7Cu31和Co14Cu24为幻数结构团簇；ConCu（38-n）混合团簇在熔化过程中均表现出热容曲线无明显宽峰的异常熔化行为；通过对团簇原子等价指数和淬火结构势能分布图对团簇异常熔化行为进行了分析表征，指出在团簇熔化过程中两种动力学稳定结构（类Oh结构与类IA结构）之间的相互竞争对团簇熔化行为的重要影响．Based on the Gupta many-body potential the ground-state geometries and melting properties of Con Cu（38-n） （n=0-38） clusters are investigated systematically by using the genetic algorithm and molec- ular dynamics simulation combined with the quenching method. Our results show that except for Co7 Cu31 which prefers to the/h-like structure as the ground-state ,all other bimetallic clusters are similar to that of the pure Cu38 （Co38） cluster with the Oh-like structure as the ground-state,and the central site is supe- rior to surface ones for replacing the Co atom（s） of the Con Cu（38-n） （n=0-38） clusters with increasing the Co atoms;From analyzing the second-order difference energy and the mixing energy,Co7 Cu3l and Co14 Cu24 are found to be the magic number dusters; There are abnormal melting behavior without obvious wide peaks in heat capacity curves for all these 38-atom clusters and which are characterized through ana- lyzing the atomic equivalence indexes and the distribution of potential energies of quenching structures, and the influence to the melting behaviors is addressed to the competition between two dynamical struc- tures （Oh-like and /h-like） in the process of cluster melting.

关 键 词：GUPTA势 分子动力学 遗传算法 团簇 熔化 

分 类 号：O469[理学—凝聚态物理] O561.1[理学—电子物理学]