Equation-of-motion coupled-cluster theory for double electron attachment with spin-orbit coupling.
Equation-of-motion coupled-cluster theory for double electron attachment with spin-orbit coupling.
复制标题
DOI：
10.1063/5.0032716
复制
发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Minggang Guo;Zhifan Wang;Fan Wang
中科院分区：
文献类型：
--
作者：
Minggang Guo;Zhifan Wang;Fan Wang
我们报告的运动方程耦合团簇（EOM-CC）方法的实施与自旋轨道耦合（SOC）的双电子附着（DEA）在CC单和双（CCSD）水平使用一个封闭的壳层参考在这项工作中。本文采用的DEA算子包含两粒子和三粒子单空穴激发，SOC包含在后Hartree-Fock处理中。利用时间反演对称性和空间对称性来降低计算成本。考虑SOC的EOM-DEA-CCSD方法使我们能够研究具有两个未成对电子的体系的SOC效应。根据我们对原子的研究结果，用EOM-DEA-CCSD方法计算了低激发态的双电离势（DIP）、激发能（EEs）和SO分裂，如果通过选择合适的闭壳层参考，可以从单激发达到相同的目标，那么对于EEs和DIP，它的精度通常高于EOM-CCSD方法.然而，EOM-DEA-CCSD方法的性能与SOC的分子是不如原子。虽然用EOM-DEA-CCSD方法计算了GaH、InH和TlH的基态和几个最低激发态的键长，但得到了合理的电子能量，并且计算了π2组态的3 π态分裂，但结果明显被低估.
We report implementation of the equation-of-motion coupled-cluster (EOM-CC) method for double electron-attachment (DEA) with spin-orbit coupling (SOC) at the CC singles and doubles (CCSD) level using a closed-shell reference in this work. The DEA operator employed in this work contains two-particle and three-particle one-hole excitations, and SOC is included in post-Hartree-Fock treatment. Time-reversal symmetry and spatial symmetry are exploited to reduce computational cost. The EOM-DEA-CCSD method with SOC allows us to investigate SOC effects of systems with two-unpaired electrons. According to our results on atoms, double ionization potentials (DIPs), excitation energies (EEs), and SO splittings of low-lying states are calculated reliably using the EOM-DEA-CCSD method with SOC. Its accuracy is usually higher than that of EOM-CCSD for EEs or DIPs if the same target can be reached from single excitations by choosing a proper closed-shell reference. However, performance of the EOM-DEA-CCSD method with SOC on molecules is not as good as that for atoms. Bond lengths for the ground and the several lowest excited states of GaH, InH, and TlH are underestimated pronouncedly, although reasonable EEs are obtained, and splittings of the 3Σ- state from the π2 configuration are calculated to be too small with EOM-DEA-CCSD.