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. 2020 Dec 8;16(12):7299-7313. doi: 10.1021/acs.jctc.0c00936. Epub 2020 Nov 16.
Nonadiabatic dynamics around conical intersections between ground and excited states are crucial to understand excited-state phenomena in complex chemical systems. With this background in mind, we present an approach combining fewest-switches trajectory surface hopping and spin-flip (SF) time-dependent (TD) density-functional tight binding (DFTB), which is a simplified version of SF-TD density functional theory (DFT) with semiempirical parametrizations, for computationally efficient nonadiabatic molecular dynamics simulations. The estimated computational time of the SF-TD-DFTB approach is several orders of magnitude lower than that of SF-TD-DFT. In addition, the proposed method reproduces the time scales and quantum yields in photoisomerization reactions of azobenzene at a level comparable with conventional ab initio approaches, demonstrating reasonable accuracy. Finally, we report a practical application of the developed technique to explore the nonradiative relaxation processes of tetraphenylethylene and its derivative with torsionally locked aromatic rings and discuss the effect of locking the rings on the excited-state lifetime.
在基态和激发态之间的圆锥交叉处的非绝热动力学对于理解复杂化学体系中的激发态现象至关重要。基于这一背景，我们提出了一种结合少数转变轨迹表面跳跃和自旋翻转（SF）含时（TD）密度泛函紧束缚（DFTB）的方法，这是一种带有半经验参数化的 SF-TD 密度泛函理论（DFT）的简化版本，用于进行计算效率高的非绝热分子动力学模拟。SF-TD-DFTB 方法的估计计算时间比 SF-TD-DFT 低几个数量级。此外，所提出的方法在与传统从头计算方法相当的水平上再现了偶氮苯光异构化反应的时间尺度和量子产率，表明具有合理的准确性。最后，我们报告了所开发技术的实际应用，以探索四苯乙烯及其具有扭转锁定芳环的衍生物的非辐射弛豫过程，并讨论了锁定环对激发态寿命的影响。
