Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
J Chem Theory Comput. 2021 Mar 9;17(3):1290-1300. doi: 10.1021/acs.jctc.0c01155. Epub 2021 Feb 12.
Nonradiative relaxation of excited molecules is central to many crucial issues in photochemistry. Condensed phases are typical contexts in which such problems are considered, and the nonradiative relaxation dynamics are expected to be significantly affected by interactions with the environment, for example, a solvent. We developed a nonadiabatic molecular dynamics simulation technique that can treat the nonradiative relaxation and explicitly include the environment in the calculations without a heavy computational burden. Specifically, we combined trajectory surface hopping with Tully's fewest-switches algorithm, a tight-binding approximated version of spin-flip time-dependent density-functional theory, and divide-and-conquer (DC) spatial fragmentation scheme. Numerical results showed that this method can treat systems with thousands of atoms within reasonable computational resources, and the error arising from DC fragmentation is negligibly small. Using this method, we obtained molecular insights into the solvent dependence of the photoexcited-state dynamics of -azobenzene, which demonstrate the importance of the environment for condensed-phase nonradiative relaxation.
激发分子的非辐射弛豫是许多光化学关键问题的核心。凝聚相是考虑此类问题的典型环境，并且非辐射弛豫动力学预计会受到与环境（例如溶剂）相互作用的显著影响。我们开发了一种非绝热分子动力学模拟技术，该技术可以处理非辐射弛豫，并在不增加计算负担的情况下在计算中明确包含环境。具体来说，我们将轨迹表面跳跃与 Tully 的最少开关算法、自旋翻转含时密度泛函理论的紧束缚近似版本以及分而治之（DC）空间碎片方案相结合。数值结果表明，该方法可以在合理的计算资源内处理包含数千个原子的系统，并且 DC 碎片产生的误差可以忽略不计。使用这种方法，我们深入了解了 -偶氮苯光激发态动力学的溶剂依赖性，这表明环境对凝聚相非辐射弛豫的重要性。
