物理化学学报 >> 2014, Vol. 30 >> Issue (3): 431-438.doi: 10.3866/PKU.WHXB201401023

理论与计算化学 上一篇    下一篇

硫族铅化物阳离子低电子态的理论研究

曹战利1, 王治钒2, 杨明理1, 王繁2   

  1. 1 四川大学原子与分子物理研究所, 成都610065;
    2 四川大学化学学院, 成都610065
  • 收稿日期:2013-12-02 修回日期:2013-12-31 发布日期:2014-02-27
  • 通讯作者: 王繁 E-mail:wangf44@gmail.com
  • 基金资助:

    国家自然科学基金(21273155)资助项目

Theory Studies on Low-Lying States of Lead Chalcogenide Cations

CAO Zhan-Li1, WANG Zhi-Fan2, YANG Ming-Li1, WANG Fan2   

  1. 1 Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China;
    2 College of Chemistry, Sichuan University, Chengdu 610065, P. R. China
  • Received:2013-12-02 Revised:2013-12-31 Published:2014-02-27
  • Contact: WANG Fan E-mail:wangf44@gmail.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21273155).

摘要:

采用我们最近发展的含旋轨耦合的运动方程耦合簇计算电离能(EOMIP-CC)方法,在CCSD级别上计算了硫族铅化物PbS、PbSe、PbTe 阳离子低电子态的平衡键长和谐振频率以及绝热和垂直电离能,得到的结果与已有的实验值吻合较好. 不考虑旋轨耦合(SOC)的情况下通过与CCSD(T)的计算结果比较,考察了三重激发对计算结果的影响,结果显示考虑三重激发的贡献后得到的键长和频率结果与实验值吻合更好. 计算结果表明PbTe+2Π态的能量分裂明显大于PbS+和PbSe+2Π态的能量分裂,但是PbTe+2Π1/22Σ1/2态之间的相互耦合则明显弱于PbS+和PbSe+中这两个态之间的耦合. PbTe+2Π1/22Σ1/2态之间耦合很弱,一方面是因为2Σ+态和2Π态的能量差比PbS+和PbSe+2Σ+态和2Π态的能量差大,另一方面还由于PbTe+2Π1/22Σ1/2态之间的旋轨耦合矩阵元只是PbS+和PbSe+2Π1/22Σ1/2态之间的旋轨耦合矩阵元的一半. 这些计算结果为PbS+、PbSe+、PbTe+阳离子的低电子态性质提供了新的理论数据,可以为将来的实验数据提供参考.

关键词: 旋轨耦合, 运动方程耦合簇方法, 电离能, 硫族铅化物

Abstract:

In this work, we investigate the low-lying states of PbS, PbSe, and PbTe cations based on a recently developed equation-of-motion coupled-cluster approach for ionization potentials (EOMIP-CC) with spin-orbit coupling (SOC) at the CCSD level. Equilibrium bond lengths, harmonic frequencies as well as vertical and adiabatic ionization energies are calculated with EOMIP-SOC-CCSD and reasonable agreement with available experimental data is achieved. The contribution of triples is estimated by comparing results at the CCSD(T) level with those from EOMIP-CCSD when SOC is neglected. Better agreement with experimental data can be obtained if the contribution of triples is included. According to our results, the splitting between 2Π state is larger in PbTe+ than that in PbS+ and PbSe+, while coupling between 2Π1/2 and 2Σ1/2 owing to SOC is more significant in PbS+ and PbSe+. This is because the energy difference between 2Π and 2Σ+ states of PbTe+ is larger than that in PbS+ and PbSe+ and the SOC matrix element between 2Π1/2 and 2Σ1/2 states in PbTe+ is only half those in PbS+ and PbSe+. The present work presents new estimates on properties of these low-lying states and could serve as new references for future experiments.

Key words: Spin-orbit coupling, Equation-of-motion coupled-cluster approach, Ionization energy, Lead chalcogenide

MSC2000: 

  • O641