Hu Ying, Xu Chao, Ye Linfeng, Gu Feng Long, Zhu Chaoyuan
Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry & Environment of South China Normal University, Guangzhou 51006, P. R. China.
Phys Chem Chem Phys. 2021 Mar 11;23(9):5236-5243. doi: 10.1039/d0cp06104b.
Global switching on-the-fly trajectory surface hopping molecular dynamics simulation was performed on the accurate TD-B3LYP/6-31G* potential energy surfaces for E-to-Z and Z-to-E photoisomerization of dMe-OMe-NAIP up to S1(ππ*) excitation. The present TD(DFT) simulation provides accurate calculation for conical intersections between the first-excited and ground states. Thus, simulated quantum yield and lifetime of 0.23 and 620 fs (0.15 and 600 fs) for E-to-Z (Z-to-E) isomerization are in good (relatively good) agreement with experimental observation of 0.25 and 480 fs (0.24 and 430 fs), respectively. Simulated results reveal that photoisomerization pathways are initially uphill to conical intersection zones on the S1 potential energy surface and then downhill to product zones. Three types of representative conical intersections are found for determining photoisomerization mechanisms: one is the rotation type responsible for reactive isomerization and the other two are close to E and Z configurations, respectively, only for nonreactive isomerization. The present conclusions can be held in general for similar large NAIP systems of photoinduced isomerization based on E and Z configurations.
在精确的TD-B3LYP/6-31G势能面上，对dMe-OMe-NAIP从E型到Z型以及从Z型到E型的光异构化进行了全局即时切换轨迹表面跳跃分子动力学模拟，直至S1(ππ)激发态。当前的TD(DFT)模拟为第一激发态和基态之间的锥形交叉点提供了精确计算。因此，E到Z（Z到E）异构化的模拟量子产率和寿命分别为0.23和620 fs（0.15和600 fs），与实验观测值0.25和480 fs（0.24和430 fs）具有良好（相对良好）的一致性。模拟结果表明，光异构化途径最初在S1势能面上朝着锥形交叉区域向上，然后朝着产物区域向下。发现了三种代表性的锥形交叉点来确定光异构化机制：一种是负责反应性异构化的旋转类型，另外两种分别接近E型和Z型构型，仅用于非反应性异构化。基于E型和Z型构型的类似大型NAIP光致异构化系统，本结论通常成立。
