化学学报 ›› 2012, Vol. 70 ›› Issue (15): 1643-1649.DOI: 10.6023/A12030032 上一篇    下一篇

研究论文

TiBn (n=1~12)团簇的结构与稳定性: 基于从头算的研究

王剑锋, 贾建峰, 马丽娟, 武海顺   

  1. 山西师范大学化学与材料科学学院 临汾 041004
  • 收稿日期:2012-03-23 出版日期:2012-08-14 发布日期:2012-07-06
  • 通讯作者: 贾建峰
  • 基金资助:

    项目受国家973预研究计划课题(No. 2010CB635110)和国家自然科学基金(No. 21103101)资助.

Structure and Stability of TiBn (n=1—12) Clusters: An ab initio Investigation

Wang Jianfeng, Jia Jianfeng, Ma Lijuan, Wu Haishun   

  1. School of Material and Chemistry Science, Shanxi Normal University, Linfen 041004
  • Received:2012-03-23 Online:2012-08-14 Published:2012-07-06
  • Supported by:

    Project supported by the National Basic Research 973 Pre-research Program of China (No. 2010CB635110) and the National Natural Science Foundation of China (No. 21103101).

基于密度泛函理论中的BPBE方法和从头算的CCSD(T)方法, 充分考虑自旋多重度, 优化并得到了TiBn (n=1~12)团簇的稳定构型. 二次差分能量分析表明n=2, 8, 10的团簇为幻数团簇. 值得注意的是, 电子相关效应对TiBn团簇的相对能量有重要影响. 密度泛函理论方法得到n=3, 7, 10团簇为幻数团簇. 对垂直电离势、垂直电子亲合势和化学硬度的分析表明, 除TiB8外, n为偶数的团簇有较小的电子亲合势和较大的电离势, 从反应性上来说, 更稳定一些.

关键词: TiBn团簇, 稳定性, 第一性原理, 电子结构

Based on the density functional theoretical (DFT) BPBE and ab initio CCSD(T) calculations, the geometries and stabilities of TiBn (n=1—12) clusters have been systematically investigated. For BPBE calculations, the orbitals of B atoms are described by the 6-311+G(d) basis set, and that of Ti atom by CEP-121G basis set. For CCSD(T) calculations, CC-PVTZ basis set is applied for both B and Ti atoms. It is found that the most stable TiBn clusters can be constructed from the most stable Bn+1 clusters when n≤6, except of TiB4, by replacing one B atom at the edge of the Bn+1 cluster with one Ti atom. With the increase of n, the TiBn clusters evolve from planar structure to three-dimensional structure. From TiB7 to TiB12, the most stable structure has nest-like structure. The calculated second-order difference of energies manifests that the magic numbers of stability are 2, 8 and 10 for the TiBn clusters in CCSD(T) level, which is different from the result of DFT calculations. Both BPBE and PW91 methods of DFT showed the magic numbers of stability are 3, 7 and 10. This difference implies the importance of electronic correlation in TiBn clusters. The vertical ionization potentials (VIP) and vertical electronic affinities (VEA) of TiBn clusters are reported at CCSD(T) level. The TiBn clusters with closed-shell electronic configuration have smaller VEA and greater VIP, which are more stable in the chemical reactivity view of point.

Key words: TiBn cluster, stability, ab initio calculation, electronic structure