Exploring Strong Field Molecular and Electron Dynamics, and Oxidation of Bio-Organic Systems

H.韦恩州立大学的Bernhard Schlegel获得了化学系理论、模型和计算方法项目的一项奖励，以促进我们对激光揭示化学反应细节的方式的理解。支持的工作是理论和计算性质的，但正在与实验科学家密切合作，他们正在激光实验室测试这些理论的预测。这些研究提供了关于如何在短而强的脉冲中传递光的信息，以跟踪化学反应发生时原子和分子的微小细节。在该项目的第二部分中，研究人员正在研究氧化物质如何在分子水平上对DNA造成损害。这个过程被认为是许多健康问题的核心，包括癌症和衰老。这项工作正在通过开发新的工具和方法来促进科学的进步，这些工具和方法将应用于许多其他科学领域。这项工作也有助于培养下一代科学家，这些科学家的项目涉及计算科学家和实验科学家之间的高度合作。研究主要有三个类别：（1）强场分子动力学研究;（2）强场中的电子动力学;（3）生物有机系统中的氧化。在（1）中，研究人员正在使用分子动力学计算研究分子在强中红外（红外）激光场中的异构化和碎裂。在某些超越玻恩-奥本海默近似的情况下，研究人员正在使用埃克塞特动力学和扩展拉格朗日动力学。在（2）中，采用含时Hartree-Fock方法、密度泛函方法和组态相互作用方法，结合真实的空间复吸收势，研究了强激光场中的电子动力学和电离过程。研究的主题包括共轭分子的角分辨电离率，电离过程中和电离后离子的电子动力学，以及异构化和碎裂反应过程中电离率的变化。在（3）中，研究了G-四链体的氧化、鸟嘌呤氧化降解过程中鸟嘌呤-赖氨酸加合物的形成以及抗坏血酸的氧化。连续溶剂化模型与空腔缩放被用来获得可靠的pKa，氧化还原电位和能量沿着反应路径。

H. Bernhard Schlegel of Wayne State University is supported by an award from the Theory, Models and Computational Methods program within the Chemistry Division for research to further our understanding of the way lasers reveal details about chemical reactions. The work supported is theoretical and computational in nature, but is being carried out in close collaboration with experimental scientists who are testing the predictions of these theories in laser laboratories. The investigations provide information on how light delivered in short, intense pulses can be used to follow minute details of atoms and molecules as chemical reactions are taking place. In a second portion of the project, the investigators are studying how damage to DNA by oxidizing species occurs at the molecular level. This process is thought to be at the core of a number of health problems, including cancer and aging. The work is promoting the progress of science by developing new tools and methods that will have application in many other areas of science. The work is also helping to train the next generation of scientists in projects that involve a high degree of collaboration between computational scientists and experimental scientists.The research has three main categories: (1) a study of strong field molecular dynamics; (2) electron dynamics in strong fields; and (3) oxidation in bio-organic systems. In (1), the investigators are studying isomerization and fragmentation of molecules in intense mid-IR (infrared) laser fields using molecular dynamics calculations. In some cases that go beyond the Born-Oppenheimer approximation, the investigators are using Ehrenfest dynamics and extended Lagrangian dynamics. In (2), time-dependent Hartree-Fock, density functional and configuration interaction methods with real space complex absorbing potentials are being used to investigate electron dynamics and ionization processes in strong laser fields. Topics under investigation include angle-resolved ionization rates in conjugated molecules, electron dynamics in ions during and after ionization, and changes in ionization rates during isomerization and fragmentation reactions. In (3), oxidation of G-quadruplexes, guanine-lysine adduct formation during oxidative degradation of guanine, and oxidation of ascorbic acid are being investigated. Continuum solvation models with cavity scaling are being used to obtain reliable pKas, redox potentials and energetics along reaction paths.