通过模拟时间分辨圆二色光谱追踪分子马达光异构化过程中的手性
Tracking Chirality during Molecular Motor Photoisomerization via Simulated Time-Resolved Circular Dichroism
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中文总结 AI 辅助
本文提出基于非绝热分子动力学系综的TRCD模拟框架，将其应用于第二代分子马达光异构化，可解析瞬态吸收无法区分的立体化学分支，为分子手性形成提供实时探测手段并给出实验预测。
中文摘要 AI 辅助
超快光谱技术被广泛用于研究光诱导过程，但在很大程度上无法探测分子手性。本文介绍了一种基于非绝热分子动力学系综模拟时间分辨电子圆二色光谱（TRCD）的框架，并将其应用于第二代分子马达[1]的光异构化研究。瞬态吸收光谱虽能捕捉整体激发态动力学，却无法区分两种光产物路径；相比之下，TRCD响应可解析立体化学分支：返回稳定P型异构体（右手螺旋）的轨迹在可见光区保留独特的手性光学带，而形成M型异构体（左手螺旋）的轨迹在通过锥形交叉点扭转时变为手性光学暗态。这种不对称性构成了可直接测量的立体化学分支特征，为分子手性的形成提供了实时探测手段，并为未来的TRCD实验提供了具体预测。
英文摘要
Ultrafast spectroscopic techniques are widely used to investigate photoinduced processes, yet they remain largely blind to molecular chirality. Here we introduce a framework for simulating time-resolved electronic circular dichroism (TRCD) along an ensemble of nonadiabatic molecular dynamics, and apply it to the photoisomerization of a second-generation molecular motor[1]. While transient absorption captures the overall excited-state dynamics, it cannot distinguish the two photoproduct pathways. The TRCD response, by contrast, resolves the stereochemical branching: trajectories returning to the stable P isomer (right-handed helix) retain a distinct chiroptical band in the visible region, whereas those forming the M isomer (leftl-handed helix) become chiroptically dark as they twist through the conical intersection. This asymmetry constitutes a directly measurable signature of the stereochemical branching, offering a real-time probe of the formation of molecular chirality and concrete predictions for future TRCD experiments.
