Transition Moments for STEOM-CCSD with Core Triples
Transition Moments for STEOM-CCSD with Core Triples
复制标题
具有核心三元组的 STEOM-CCSD 的过渡时刻
DOI：
10.1021/acs.jctc.3c00415
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发表时间：
2023
影响因子：
5.5
通讯作者：
Matthews, Devin A.
中科院分区：
文献类型：
--
作者：
Simons, Megan;Matthews, Devin A.
相似变换运动方程耦合团簇理论（英语：Similarity-transformed equation of motion coupled cluster theory，缩写为STEOM-CC）是一种替代激发态运动方程耦合团簇理论（英语：Equation of motion coupled cluster theory for excited states，缩写为EOMEE-CC）的方法，它使用哈密顿量的第二次相似变换，然后在小的（CI类单）激发空间中对角化，即使在变换中包括单激发和双激发。除了垂直激发能之外，跃迁矩测量状态之间的相互作用的强度，确定吸收，发射和其他过程。在STEOM-CCSD中，跃迁矩以一种直接的方式计算为使用左手和右手解的双正交期望值，与EOMEE-CC的主要区别在于包含了变换算子。我们最近开发了一个扩展的STEOM-CCSD核心激发，CVS-STEOM-CCSD+cT，其中包括三重激发和著名的核心电离势计算的核心价分离。在这项工作中，我们推导出的核心激发态与核心三重激发，包括地面到核心激发和价到核心激发跃迁的跃迁时刻。将CVS-STEOM-CCSD+cT方法计算的跃迁矩的改进与我们先前发表的小分子基准集的标准CVS-STEOM-CCSD和CVS-EOOM-CCSD进行比较。
Similarity-transformed equation-of-motion coupled-cluster theory (STEOM-CC) is an alternative approach to equation-of-motion coupled-cluster theory for excited states (EOMEE-CC), which uses a second similarity transformation of the Hamiltonian, followed by diagonalization in a small (CI singles-like) excitation space, even when single and double excitations are included in the transformation. In addition to vertical excitation energies, transition moments measure the strength of the interactions between states determining absorption, emission, and other processes. In STEOM-CCSD, transition moments are calculated in a straightforward manner as biorthogonal expectation values using both the left- and right-hand solutions, with the main difference from EOMEE-CC being the inclusion of the transformation operator. We recently developed an extension of STEOM-CCSD to core excitations, CVS-STEOM-CCSD+cT, which includes triple excitations and the well-known core-valence separation for the core ionization potential calculations. In this work, we derived transition moments for core-excited states with core triple excitations, including both ground-to-core-excited and valence-to-core-excited transitions. The improvement of the computed transition moments of the CVS-STEOM-CCSD+cT method is compared to standard CVS-STEOMEE-CCSD and CVS-EOMEE-CCSD for our previously published small-molecule benchmark set.