Parson William W
Department of Biochemistry, University of Washington , Seattle, Washington 98195, United States.
J Phys Chem B. 2016 Nov 10;120(44):11412-11418. doi: 10.1021/acs.jpcb.6b08803. Epub 2016 Oct 27.
The rates of nonadiabatic electron-transfer reactions depend on four main factors: the probability of finding the system in a conformation in which the reactant and product states have the same energy, the electronic coupling that drives oscillations between the two diabatic states, the dephasing that damps these oscillations, and the vibrational or electronic relaxations that trap the product state by transferring energy to the surroundings. This paper develops a simple expression that combines these factors in a relatively realistic manner. Values for all the parameters in the expression can be obtained from microscopic quantum-mechanical/molecular-mechanical simulations. The theory is tested by calculations of the rates of electron transfer from excited indole rings to a variety of acceptors in peptides and indole-acrylamide compounds. For the systems that are studied, the theory gives considerably better agreement with experiment than expressions that do not consider the rates of vibrational relaxations and dephasing.
系统处于反应物和产物状态具有相同能量的构象中的概率、驱动两个绝热状态之间振荡的电子耦合、使这些振荡衰减的去相位以及通过将能量转移到周围环境来捕获产物状态的振动或电子弛豫。本文推导了一个简单的表达式，以相对现实的方式将这些因素结合起来。该表达式中所有参数的值都可以从微观量子力学/分子力学模拟中获得。通过计算从激发的吲哚环到肽和吲哚 - 丙烯酰胺化合物中各种受体的电子转移速率来检验该理论。对于所研究的系统，该理论与实验的吻合度比不考虑振动弛豫和去相位速率的表达式要好得多。
