Theoretical Studies of Proton-Coupled Electron Transfer Reactions

宾夕法尼亚州立大学的Sharon Hammes-Schiffer获得了化学系理论、模型和计算方法项目的一项奖励，以开展质子耦合电子转移（PCET）反应的理论研究。PI和她的研究小组正在进行四个相关项目：1）开发网格和核电子轨道（NEO）方法来分析电子-质子非绝热效应，以阐明PCET反应的机制。质子转移反应的电子nonadiabaticity的程度提供了一个定量诊断区分氢原子转移（HAT）和PCET，其中HAT是电子绝热和PCET是电子非绝热。2)开发计算电子-质子振动耦合的方法，以预测PCET反应的速率常数和动力学同位素效应的趋势。 3)开发研究光诱导PCET反应动力学的方法。溶剂和溶质核在绝热电子-质子振动表面上的传播采用表面跳跃方法，以包含绝热态之间的非绝热跃迁4）模拟DNA中光激发PCET的超快动力学。 质子耦合电子转移（PCET）反应在电化学、光合作用、呼吸作用和酶反应等广泛的化学和生物过程中起着关键作用。 从这个项目产生的软件被广泛提供给更广泛的社区被列入GAMESS计算化学软件包的公共版本。 这项研究的进展通过一个专门用于PCET的网站提供给公众，该网站包含教程，代码和交互式Java servletes（https：webpcet.chem.psu.edu）。

Sharon Hammes-Schiffer of the Pennsylvania State University is supported by an award from the Theory, Models and Computational Methods program in the Chemistry division to carry out research on theoretical studies of proton-coupled electron transfer (PCET) reactions. The PI and her research group are pursuing four related projects: 1) developing both grid and nuclear-electronic orbital(NEO) methods for analyzing the electron-proton nonadiabatic effects to elucidate the mechanisms of PCET reactions. The degree of electronic nonadiabaticity for the proton transfer reaction provides a quantitative diagnostic for differentiating between hydrogen atom transfer (HAT) and PCET, where HAT is electronically adiabatic and PCET is electronically nonadiabatic. 2) developing methods to calculate electron-proton vibronic couplings to enable the prediction of trends in rate constants and kinetic isotope effects for PCET reactions. 3) developing methods for studying the dynamics of photoinduced PCET reactions. The solvent and solute nuclei are propagated on adiabatic electron-proton vibronic surfaces using a surface hopping method to incorporate nonadiabatic transitions among the adiabatic states 4) modeling the ultrafast dynamics of photo-excited PCET in DNA. Proton-coupled electron transfer (PCET) reactions play a critical role in a wide range of chemical and biological processes, including electrochemistry, photosynthesis, respiration, and enzyme reactions. Software resulting from this project is made widely available to the broader community by being included in the public version of the GAMESS computational chemistry software package. The advances from this research are provided to the public through a website devoted to PCET that contains tutorials, code and interactive Java servletes (https://webpcet.chem.psu.edu).