物理化学学报 >> 1993, Vol. 9 >> Issue (05): 642-649.doi: 10.3866/PKU.WHXB19930514

研究论文 上一篇    下一篇

锡原子簇的结构和相对稳定性

李思殿; R.约翰斯顿; J.莫诺   

  1. 山西运城高等专科学校 运城 044000;萨赛克斯大学分子科学院,BNI 9QJ, UK
  • 收稿日期:1992-04-09 修回日期:1992-09-20 发布日期:1993-10-15
  • 通讯作者: 李思殿

Structures and Relative Stabilities of tin Clusters

Li Si-Dian; R.Johnston; J.Murrell   

  1. Yuncheng Advanced Training College, Yuncheng 044000; Shanxi; University of Sussex, Brighton BNI 9QJ, UK
  • Received:1992-04-09 Revised:1992-09-20 Published:1993-10-15
  • Contact: Li Si-Dian

摘要: 基于从固体锡确立的多体展开势能函数, 采用座标直接优化方法预测了锡原子簇分子(Sn_2-Sn_(300))的结构和相对稳定性, 并用蒙特卡罗方法验证了有关小的原子簇(Sn_2-Sn_(15))的所有结果. 优化结果表明: (1)小的锡原子簇分子(Sn_2-Sn_(15))倾向于密堆积结构, 与锡晶体结构无关; (2)中等大小的簇分子, 如Sn_(47), Sn_(71), Sn_(87)及Sn_(147)等, 则呈α-Sn晶体的畸变结构, 其外围各层原子到中心原子的距离受到压缩, 且某些层被劈裂为两层或多层; (3)随着原子簇尺寸的进一步增大, 结构畸变逐渐减弱, 簇分子的单原子平均结合能缓慢增大, 其外椎值大约在Sn_(740)处趋近于α-Sn的结合能.

关键词: 锡原子簇, 结构, 稳定性, 势能函数

Abstract: A many-body expansion interatomic potential obtained from bulk tin was used to predict the structures and energies of small and medium size tin clusters (Sn_2-Sn_(300)). The optimized results show that small tin clusters (Sn_2-Sn_(15)) prefer to take compact structures as their most stable configuration, all unrelated with the bulk lattice; while medium tin clusters, like, Sn_(47), Sn_(71), Sn_(87), and Sn_(147), are still kept in shell structures which are distortions of the microcrystalline fragments of solid tin, with all the shells compressed and some shells split. The energy per-atom of these clusters increases steadily with the increasing of the cluster size, approaching the cohesive energy of α-tin at about Sn_(740) (extrapolated), where the most stable structure should match the bulk lattice except for a few percents of surface atoms.

Key words: Tin clusters, Structures, Stabilities, Potential energy function