Pokhilko Pavel, Krylov Anna I
Department of Chemistry , University of Southern California , Los Angeles , California 90089-0482 , United States.
J Phys Chem Lett. 2019 Sep 5;10(17):4857-4862. doi: 10.1021/acs.jpclett.9b02120. Epub 2019 Aug 12.
One-particle transition density matrices and natural transition orbitals enable quantitative description of electronic transitions and interstate properties involving correlated many-body wave functions within the molecular orbital framework. Here we extend the formalism to the analysis of tensor properties, such as spin-orbit couplings (SOCs), which involve states of different spin projection. By using spinless density matrices and Wigner-Eckart's theorem, the approach allows one to treat the transitions between states with arbitrary spin projections in a uniform way. In addition to a pictorial representation of the transition, the analysis also yields quantitative contributions of hole-particle pairs into the overall many-body matrix elements. In particular, it helps to rationalize the magnitude of computed SOCs in terms of El-Sayed's rules. The capabilities of the new tool are illustrated by the analysis of the equation-of-motion coupled-cluster calculations of two transition metal complexes.
单粒子跃迁密度矩阵和自然跃迁轨道能够在分子轨道框架内对涉及相关多体波函数的电子跃迁和态间性质进行定量描述。在此，我们将该形式体系扩展至张量性质的分析，例如涉及不同自旋投影态的自旋 - 轨道耦合（SOCs）。通过使用无自旋密度矩阵和维格纳 - 埃卡特定理，该方法能够以统一的方式处理具有任意自旋投影的态之间的跃迁。除了对跃迁进行直观表示外，该分析还能得出空穴 - 粒子对在整体多体矩阵元中的定量贡献。特别是，它有助于根据埃尔 - 赛义德规则来解释计算得到的SOCs的大小。通过对两种过渡金属配合物的运动方程耦合簇计算分析，展示了这一新工具的功能。
