Runeson Johan E, Mannouch Jonathan R, Amati Graziano, Fiechter Marit R, Richardson Jeremy O
Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
Chimia (Aarau). 2022 Jun 29;76(6):582-588. doi: 10.2533/chimia.2022.582.
Many chemical reactions exhibit nonadiabatic effects as a consequence of coupling between electronic states and/or interaction with light. While a fully quantum description of nonadiabatic reactions is unfeasible for most realistic molecules, a more computationally tractable approach is to combine a classical description of the nuclei with a quantum description of the electronic states. Combining the formalisms of quantum and classical dynamics is however a difficult problem for which standard methods (such as Ehrenfest dynamics and surface hopping) may be insufficient. In this article, we review a new trajectory-based approach developed in our group that is able to describe nonadiabatic dynamics with a higher accuracy than previous approaches but for a similar level of computational effort. This method treats the electronic states with a phase-space representation for discrete-level systems, which in the two-level case is analogous to a spin-½. We point out the key features of the method and demonstrate its use in a variety of applications, including ultrafast transfer through conical intersections, damped coherent excitation under coupling to a strong light field, and nonlinear spectroscopy of light-harvesting complexes.
许多化学反应由于电子态之间的耦合和/或与光的相互作用而表现出非绝热效应。虽然对大多数实际分子来说，对非绝热反应进行完全量子描述是不可行的，但一种计算上更易于处理的方法是将原子核的经典描述与电子态的量子描述相结合。然而，将量子动力学和经典动力学的形式体系结合起来是一个难题，标准方法（如埃伦费斯特动力学和表面跳跃）可能并不适用。在本文中，我们回顾了我们小组开发的一种基于轨迹的新方法，该方法能够以比以前的方法更高的精度描述非绝热动力学，但计算量相当。该方法用离散能级系统的相空间表示来处理电子态，在两能级情况下类似于自旋-1/2。我们指出了该方法的关键特征，并展示了其在各种应用中的用途，包括通过锥形交叉点的超快转移、与强光场耦合下的阻尼相干激发以及光捕获复合物的非线性光谱。
