Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Phys Chem B. 2010 Sep 30;114(38):12319-32. doi: 10.1021/jp1051547.
A theoretical formulation for modeling photoinduced nonequilibrium proton-coupled electron transfer (PCET) reactions in solution is presented. In this formulation, the PCET system is described by donor and acceptor electron-proton vibronic free energy surfaces that depend on a single collective solvent coordinate. Dielectric continuum theory is used to obtain a generalized Langevin equation of motion for this collective solvent coordinate. The terms in this equation depend on the solvent properties, such as the dielectric constants, relaxation time, and molecular moment of inertia, as well as the solute properties characterizing the vibronic surfaces. The ultrafast dynamics following photoexcitation is simulated using a surface hopping method in conjunction with the Langevin equation of motion. This methodology is used to examine a series of model photoinduced PCET systems, where the initial nonequilibrium state is prepared by vertical photoexcitation from the ground electronic state to the donor electronic state. Analysis of the dynamical trajectories provides insight into the interplay between the solvent dynamics and the electron-proton transfer for these types of processes. In addition, these model studies illustrate how the coupling between the electron-proton transfer and the solvent dynamics can be tuned by altering the solute and solvent properties.
本文提出了一种用于模拟溶液中光诱导非平衡质子耦合电子转移（PCET）反应的理论方法。在该方法中，PCET 体系由依赖于单个集体溶剂坐标的供体和受体电子质子振动自由能表面来描述。介电连续体理论用于获得这个集体溶剂坐标的广义朗之万运动方程。该方程中的项取决于溶剂的性质，如介电常数、弛豫时间和分子转动惯量，以及描述振动表面的溶质性质。超快动力学是通过表面跳跃法结合朗之万运动方程来模拟光激发后的动力学过程。该方法用于研究一系列模型光诱导 PCET 体系，其中初始非平衡态是通过从基态到给电子态的垂直光激发来制备的。对动力学轨迹的分析提供了对这些类型过程中溶剂动力学和电子质子转移之间相互作用的深入了解。此外，这些模型研究说明了如何通过改变溶质和溶剂的性质来调节电子质子转移和溶剂动力学之间的耦合。
