化学学报 ›› 2004, Vol. 62 ›› Issue (18): 1689-1694. 上一篇    下一篇

研究论文

过渡金属纯簇和混合簇的密度泛函研究:Nb4,Co4和Nb2Co2

王娴, 林梦海, 张乾二   

  1. 厦门大学化学系, 固体表面物理化学国家重点实验室, 厦门, 361005
  • 投稿日期:2004-04-15 修回日期:2004-06-03 发布日期:2014-02-17
  • 通讯作者: 林梦海,E-mail:linmh@xmu.edu.cn;Fax:0592-2184708. E-mail:linmh@xmu.edu.cn
  • 基金资助:
    国家自然科学基金(Nos.90206038,20373053)和福建省重大项目基金(No.2002F010)资助项目.

Density Functional Theory Study of Pure and Mixed Transition-metal Clusters: Nb4, Co4 and Nb2Co2

WANG Xian, LIN Meng-Hai, ZHANG Qian-Er   

  1. Department of Chemistry, Xiamen University, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen 361005
  • Received:2004-04-15 Revised:2004-06-03 Published:2014-02-17

用密度泛函方法对过渡金属双原子Nb2,Co2和NbCo的电子态进行研究,得到三者的基态分别为3g-,5g+3△.并以此为基础,讨论四核簇Nb4,Co4和No2Co2的成键情况,发现稳定的单金属簇Nb4具有高对称性的密堆结构,稳定的Co4具有低对称性的变形封闭结构,两者都是典型的金属键;而Nb2Co2在封闭式结构中是一般的金属键,在线形结构中有强弱交替的定域键,Nb原子易相互靠近成键,Co原子趋于远离不成键.三种团簇的多重度以Nb4<Nb2Co2<Co4顺序依次升高.

关键词: 过渡金属团簇, 金属键, 定域键, 铌,

The transition-metal dimers Nb2, Co2 and diatomics NbCo have been calculated using density functional theory. Their ground states were predicted to be 3g-, 5g+ and 3Δ, respectively. The tetramers Nb4, Co4 and Nb2Co2 have been discussed at UBP86 level. The results show that Nb4 clusters have compact structures with high symmetries, while Co4 have distortion structures with low symmetries. Both of them have normal metal bonds. On the other hand, mixed clusters Nb2Co2 have not only three- and two-dimensional structures, but also straight-line structures with the weak-strong alternant bonds. Two Nb atoms tend to bond each other, while two Co atoms tend to dissociate. The multiplicities of tetramers follow the order of Nb4Nb2Co2Co4.

Key words: transition-metal cluster, metal bond, local bond, niobium, cobalt