| 碱金属原子簇的结构和稳定性 |
| STRUCTURES AND STABILITIES OF ALKALI METAL CLUSTERS |
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| 摘要: 基于从体心立方碱金属晶体优化确立的多体展开势能函数,本文通过坐标优化研究了碱金属原子簇Xn(X=Li,Na,K,Rb,Cs)的结构和稳定性。发现:(1)Xn原子簇(n=4-21)倾向于形成畸变四面体结构单元(Td)的密堆积,分子表面被三元环(D3h)所覆盖。其中X7-X15最优结构中包含五角双锥X7(D5h)结构单元,具有区域五重对称轴;(2)“微观晶体碎片”的分层优化结果表明,体心立方、面心立方及六方密堆积类展状原子簇具有相近的结合能。且均远比相应原子数的简单立方及金刚石类层状原子簇更为稳定;(3)原子簇的单原子平均结合能呈增大趋势,向体心立方碱金属晶体的结合能缓慢趋近。 |
| 关键词: 多体展开势能函数 碱金属原子簇 结构 稳定性 表面结构 |
| 基金项目: 山西省回国留学基金 |
| Abstract: The structures and stabilitics of alkali metal clusters Xn(X=Li,Na,K,Rb,Cs) were studied based upon the many-body expansion potential energy functions optimized frombody-centered cubic alkali metals.The optimum strictures of small Xn clustcrs(n=2-21) arefound to be close-packed structures of distorted tetrabcdrons(X4,Td) with molecular surfacescovered exclusively with three-membered rings (X3, D3h).The most stable X7 is a pentagonalbipyramid(D5h)and X7-X15 are derivatives of X7 as strictures of inter-linkcd pentagonalbipyramidal units,suggesting a five-fold local symmetry growth pattern of Xn in the range of n=7-15.Radially optimized body-centered cubic,face-centered cubic,and hexagonalclose-packed shell-clusters (n=5-90) are close in binding energies and all much more stablethan diamond and simple cubic shell-clusters.The binding energies pereatom of these clustersincrease slowly and approach the cohesive energies of coresponding bulk metals gradually. |
| Keywords: many-body expansion potential energy function alkali metal cluster structure stabililty surface structure |
| 投稿时间：1993-09-08 |
| 摘要点击次数: 1720 |
| 全文下载次数: 2289 |
| 李思殿,王继武,程晓燕.碱金属原子簇的结构和稳定性[J].无机化学学报,1994,10(3):305-310. |
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