Absorption Spectra of Solids from Periodic Equation-of-Motion Coupled-Cluster Theory
Absorption Spectra of Solids from Periodic Equation-of-Motion Coupled-Cluster Theory
复制标题
周期运动方程耦合团簇理论的固体吸收光谱
DOI：
10.1021/acs.jctc.1c00692
复制
发表时间：
2021
影响因子：
5.5
通讯作者：
Berkelbach, Timothy C.
中科院分区：
文献类型：
--
作者：
Wang, Xiao;Berkelbach, Timothy C.
用基于高斯周期运动方程的单激发和双激发耦合团簇理论(EOM-CCSD)计算了六种三维半导体和绝缘体的从头算吸收光谱。通过求解每个频率下的线性方程组，可以有效地计算光谱，从而获得数十电子伏特的能量范围，而无需显式列举激发态。我们评估了与布里渊区采样、冻结轨道和分区EOM-CCSD近似相关的成本节约近似的影响。尽管我们最收敛的光谱显示的线形与实验光谱很好地吻合，但它们被均匀地移动到更高的能量约1 eV，这不能用剩余的有限尺寸误差来解释。我们试探性地将这种差异归因于振动效应和剩余的电子关联，即三重激发和更高激发。
We present ab initio absorption spectra of six three-dimensional semiconductors and insulators calculated using Gaussian-based periodic equation-of-motion coupled-cluster theory with single and double excitations (EOM-CCSD). The spectra are calculated efficiently by solving a system of linear equations at each frequency, giving access to an energy range of tens of electronvolts without explicit enumeration of excited states. We assess the impact of cost-saving approximations associated with Brillouin zone sampling, frozen orbitals, and the partitioned EOM-CCSD approximation. Although our most converged spectra exhibit line shapes that are in good agreement with experimental spectra, they are uniformly shifted to higher energies by about 1 eV, which is not explained by the remaining finite-size errors. We tentatively attribute this discrepancy to a combination of vibrational effects and the remaining electron correlation, i.e., triple excitations and above.