Lai Yifan, Geva Eitan
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
J Chem Phys. 2022 Sep 14;157(10):104115. doi: 10.1063/5.0106888.
Quantum master equations (QMEs) provide a general framework for describing electronic dynamics within a complex molecular system. Off-diagonal QMEs (OD-QMEs) correspond to a family of QMEs that describe the electronic dynamics in the interaction picture based on treating the off-diagonal coupling terms between electronic states as a small perturbation within the framework of second-order perturbation theory. The fact that OD-QMEs are given in terms of the interaction picture makes it non-trivial to obtain Schrödinger picture electronic coherences from them. A key experimental quantity that relies on the ability to obtain accurate Schrödinger picture electronic coherences is the absorption spectrum. In this paper, we propose using a recently introduced procedure for extracting Schrödinger picture electronic coherences from interaction picture inputs to calculate electronic absorption spectra from the electronic dynamics generated by OD-QMEs. The accuracy of the absorption spectra obtained this way is studied in the context of a biexciton benchmark model, by comparing spectra calculated based on time-local and time-nonlocal OD-QMEs to spectra calculated based on a Redfield-type QME and the non-perturbative and quantum-mechanically exact hierarchical equations of motion method.
量子主方程（QMEs）为描述复杂分子系统中的电子动力学提供了一个通用框架。非对角量子主方程（OD-QMEs）对应于一类量子主方程，它们基于将电子态之间的非对角耦合项视为二阶微扰理论框架内的小扰动，来描述相互作用绘景中的电子动力学。由于OD-QMEs是在相互作用绘景下给出的，因此从它们中获得薛定谔绘景电子相干性并非易事。依赖于获得精确薛定谔绘景电子相干性能力的一个关键实验量是吸收光谱。在本文中，我们提议使用一种最近引入的从相互作用绘景输入中提取薛定谔绘景电子相干性的方法，来根据OD-QMEs产生的电子动力学计算电子吸收光谱。通过将基于时间局部和时间非局部OD-QMEs计算的光谱与基于雷德菲尔德型量子主方程以及非微扰且量子力学精确的运动方程层级方法计算的光谱进行比较，在双激子基准模型的背景下研究了以此方式获得的吸收光谱的准确性。
