Sirjoosingh Andrew, Hammes-Schiffer Sharon
Department of Chemistry, 104 Chemistry Building, Pennsylvania State University , University Park, Pennsylvania 16802, United States.
J Chem Theory Comput. 2011 Sep 13;7(9):2831-41. doi: 10.1021/ct200356b. Epub 2011 Aug 18.
A scheme for the rigorous construction of charge-localized diabatic electron-proton vibronic states for proton-coupled electron transfer (PCET) reactions is presented. The diabatic electronic states are calculated using an adiabatic-to-diabatic transformation designed to ensure that the first-order nonadiabatic couplings with respect to a specified one-dimensional reaction coordinate vanish exactly. This scheme is applied to both symmetric and asymmetric PCET systems with several different one-dimensional reaction coordinates, including the hydrogen transfer coordinate, a normal mode coordinate, and the intrinsic reaction coordinate. This approach is also extended to describe the three-dimensional motion of the transferring hydrogen. The diabatic electronic states exhibit relatively invariant charge distributions along the reaction coordinate and are in excellent agreement with the analogous states obtained from the generalized Mulliken-Hush and Boys localization methods. Furthermore, these diabatic electronic states are combined with the associated proton vibrational wave functions to generate charge-localized electron-proton vibronic states that describe one- or three-dimensional hydrogen motion. These electron-proton vibronic states can be used to calculate the vibronic couplings, rate constants, and kinetic isotope effects of PCET reactions.
本文提出了一种用于质子耦合电子转移（PCET）反应的电荷局域非绝热电子 - 质子振动态的严格构建方案。非绝热电子态通过绝热到非绝热的变换来计算，该变换旨在确保相对于指定的一维反应坐标的一阶非绝热耦合精确消失。此方案应用于具有几种不同一维反应坐标的对称和非对称PCET系统，包括氢转移坐标、一个正则模坐标和内禀反应坐标。该方法还扩展到描述转移氢的三维运动。非绝热电子态沿反应坐标呈现相对不变的电荷分布，并且与通过广义穆利肯 - 赫什（Mulliken - Hush）和博伊斯（Boys）定域化方法获得的类似态高度吻合。此外，这些非绝热电子态与相关的质子振动波函数相结合，以生成描述一维或三维氢运动的电荷局域电子 - 质子振动态。这些电子 - 质子振动态可用于计算PCET反应的振转耦合、速率常数和动力学同位素效应。
