Theoretical Studies of Proton-Coupled Electron Transfer Reactions

宾夕法尼亚州立大学的Sharon Hammes-Schiffer得到了化学系理论、模型和计算方法计划的支持，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的项目：1)发展网格和核-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非绝热程度为区分氢原子转移(HAT)和PCET提供了一个定量诊断，其中HAT是电子绝热的，PCET是电子非绝热的。2)发展计算电子-质子振动耦合的方法，以便能够预测PCET反应的速率常数和动力学同位素效应的趋势。3)发展研究光诱导PCET反应动力学的方法。用表面跳跃方法在绝热电子-质子振动表面上传播溶剂和溶质核，以包含绝热状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)反应在包括电化学、光合作用、呼吸作用和酶反应在内的广泛的化学和生物过程中发挥着关键作用。这个项目产生的软件通过包含在GamesS计算化学软件包的公共版本中而广泛地提供给更广泛的社区。这项研究的进展通过一个致力于PCET的网站向公众提供，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).