高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (11): 2354.doi: 10.7503/cjcu20190300

• 物理化学 • 上一篇    下一篇

Al6ONa2组装Zintl相晶体的理论研究

张兆燕,陈宏善()   

  1. 西北师范大学物理与电子工程学院, 兰州 730070
  • 收稿日期:2019-05-24 出版日期:2019-11-10 发布日期:2019-10-12
  • 通讯作者: 陈宏善 E-mail:chenhs@nwnu.edu.cn
  • 基金资助:
    国家自然科学基金资助(11664034)

Theoretical Studies on the Zintl Crystals Assembled by Al6ONa2 Clusters

ZHANG Zhaoyan,CHEN Hongshan()   

  1. College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
  • Received:2019-05-24 Online:2019-11-10 Published:2019-10-12
  • Contact: CHEN Hongshan E-mail:chenhs@nwnu.edu.cn
  • Supported by:
    ? Supported by the National Natural Science Foundation of China(11664034)

摘要:

结合遗传算法和从头算方法确定了Al6ONa2的低能异构体. 揭示了以非金属为中心的Al-Na团簇的幻数行为. 金属团簇离域的凝胶轨道和非金属原子的价轨道作用形成定域在O原子上的成键轨道和离域在整个团簇上的反键轨道, 26个价电子形成s 2p 6S 2P 6D 10的闭合壳层强幻数电子结构. Al6O 2-与Na +通过离子键结合, Al6O 2-的电子结构符合Wade-Mingos规则. 基于超原子阴离子Al6O 2-具有较强的热稳定性和化学惰性, 组装了具有Pn 3 ˉ mFd 3 ˉ m空间群的AB2型晶体结构, Al6ONa2团簇的结合能为-23.44 eV, 组装结构中团簇单元间的相互作用能分别为-1.19和-1.53 eV. 晶体结构的电子结构分析表明, 2种组装晶体均为宽带隙半导体. 声子色散曲线和弹性常数的计算表明组装晶体具有良好的动力学稳定性.

关键词: 幻数团簇, 超原子阴离子, 电子结构, 团簇组装

Abstract:

The low energy isomers of Al6ONa2 were determined by genetic algorithm combined with ab initio calculations. The results reveal the strong magic behavior of O-centered Al-Na cluster with 26 electrons. The interaction of atomic O orbitals and Jellium orbitals of the metal moieties forms bonding orbitals localized on O atom and antibonding orbitals delocalized on the whole cluster. The hetero metal cluster with 26 electrons form closed s 2p 6S 2P 6D 10 shells and corresponds to a strong magic structure. The Na + cations are ionically bonded to the Al6O 2- anion. The electronic structures of Al6O 2- core also accord with the Wade-Mingos rule. Based on the peculiar stability of the superatomic anion Al6O 2-, we predicted two AB2 clusters with Pn 3 ˉ m and Fd 3 ˉ m point groups by density functional theory(DFT) calculations. The binding energy of Al6ONa2 cluster is -23.44 eV, and the interaction energy between the clusters in the crystal structures is -1.19 and -1.53 eV. The electronic structures of the crystals indicate that both the assembled structures have semiconductor properties. The phonon dispersion curves and elastic constants show that the assembled crystals are dynamically and mechanically stability.

Key words: Magic cluster, Superatomic anion, Electronic structure, Cluster assemble

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