Acta Chim. Sinica ›› 2016, Vol. 74 ›› Issue (9): 758-763.DOI: 10.6023/A16050230 Previous Articles     Next Articles



黄敏, 徐畅, 程龙玖   

  1. 安徽大学化学化工学院 合肥 260301
  • 投稿日期:2016-05-11 发布日期:2016-08-10
  • 通讯作者: 程龙玖
  • 基金资助:


Density Functional Theory Studies of the Binary Systems[BxAl13-x]- (x=0~13)

Huang Min, Xu Chang, Cheng Longjiu   

  1. School of Chemistry and Chemical Engineering, Anhui University, Hefei 260301
  • Received:2016-05-11 Published:2016-08-10
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21273008, 21573001).

In this paper, the global minimum search and structural optimization for the B-Al binary clusters [BxAl13-x]- (x=0~13) are performed using the genetic algorithm (GA) method coupled with density functional theory (DFT). The effects of composition on the atomic structures, electronic properties including the energy gaps and vertical detachment energies of B-Al binary clusters are discussed. The results distinctly reveal a three dimensional (3D) to (quasi-)planar (2D) structural transition as a function of x upon increasing the number of boron atoms. When x is in the range of 0 to 7, the clusters are Al-rich and the B-Al binary systems maintain the 3D structure. Whereas, the binary system trends to be quasi-planar structure, and the critical B:Al ratios for the 2D-3D transition are between x=7 and 8. To study the stability of the [BxAl13-x]- clusters, we defined the relative energy (Erel=E([BxAl13-x]-)-xE(B13-)/13–yE(Al13-)/13), where the cluster with a more negative Erel is more stable. At x=1, Erel is the most negative, indicating the highest stability. In order to further understand the stability of clusters, the vertical detachment energies (VDE) and the HOMO-LUMO energy gaps (EH-L) of [BxAl13-x]- (x=0~13) clusters are also calculated. The results show that the energy decreases with the increasing number of B atoms, indicating a lower stability. The largest EH-L of BAl12- cluster indicates that it is the most stable among all the series of this clusters. Molecular orbitals (MO) of BAl12- cluster are analyzed and the result shows that the electronic shells of 1s2 and 1p6 are virtually unchanged when the central Al atom is replaced by the B atom. It also indicates that the electron shell closing model could be regarded as a simple but valid tool for explaining the structures and stabilities of metal clusters. Chemical bonding analysis by Adaptive Natural Density Partitioning (AdNDP) method for the B13- cluster reveals that it is a π-antiaromatic system with 8 delocalized π-electrons.

Key words: density functional theory, [BxAl13-x]- (x=0~13) clusters, optimization, molecular orbitals, adaptive natural density partitioning