Li Zhaofa, Peng Jiawei, Zhu Yifei, Xu Chao, Gelin Maxim F, Gu Feng Long, Lan Zhenggang
School of Chemistry, South China Normal University, Guangzhou 510006, China.
MOE Key Laboratory of Environmental Theoretical Chemistry, SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety, School of Environment, South China Normal University, Guangzhou 510006, China.
Molecules. 2025 Mar 24;30(7):1439. doi: 10.3390/molecules30071439.
Conical intersections (CIs) are the most efficient channels of photodeactivation and energy transfer, while femtosecond spectroscopy is the main experimental tool delivering information on molecular CI-driven photoinduced processes. In this work, we undertake a comprehensive ab initio investigation of the CI-mediated internal conversion in fulvene by simulating evolutions of electronic populations, bond lengths and angles, and time-resolved transient absorption (TA) pump-probe (PP) spectra. TA PP spectra are evaluated on the fly by combining the symmetrical quasiclassical/Meyer-Miller-Stock-Thoss (SQC/MMST) dynamics and the doorway-window representation of spectroscopic signals. We show that the simulated time-resolved TA PP spectra reveal not only the population dynamics but also the key nuclear motions as well as mode-mode couplings. We also demonstrate that TA PP signals are not only experimental observables: They can also be considered as information-rich purely theoretical observables, which deliver more information on the CI-driven dynamics than conventional electronic populations. This information can be extracted by the appropriate theoretical analyses of time-resolved TA PP signals.
锥形交叉点（CIs）是光致失活和能量转移最有效的通道，而飞秒光谱是提供有关分子CI驱动的光诱导过程信息的主要实验工具。在这项工作中，我们通过模拟电子布居、键长和键角的演化以及时间分辨瞬态吸收（TA）泵浦-探测（PP）光谱，对富烯中CI介导的内转换进行了全面的从头算研究。通过结合对称准经典/迈耶-米勒-斯托克-托斯（SQC/MMST）动力学和光谱信号的门道-窗口表示，实时评估TA PP光谱。我们表明，模拟的时间分辨TA PP光谱不仅揭示了布居动力学，还揭示了关键的核运动以及模式-模式耦合。我们还证明，TA PP信号不仅是实验可观测的：它们还可以被视为信息丰富的纯理论可观测值，与传统的电子布居相比，它们能提供更多关于CI驱动动力学的信息。这些信息可以通过对时间分辨TA PP信号进行适当的理论分析来提取。
