瑞士苏黎世联邦理工学院Wrner, Hans Jakob团队利用时间分辨光电子能谱揭示了气、液相中二苯乙烯超快异构化过程的不同时间尺度。相关研究成果于2022年8月11日发表于国际顶尖学术期刊《自然—化学》。

直接对比气相和液相中的超快激发态动力学对于理解复杂环境的影响至关重要。以前的研究通常依赖于不同的光谱观测，这使得直接比较具有挑战性。

该文中，研究人员将极紫外时间分辨光电子能谱应用于气态和液态顺式二苯乙烯，揭示了其异构化的耦合电子和核动力学原因。研究人员测量跟踪从激发到最终产物的整个反应路径的激发态波包。研究人员在物质的两个相阶段观察到相干激发态振动动力学，这两个阶段持续到最终产物，从而能够表征S1–S0圆锥交点的分支空间。研究人员观察到液相中弛豫时间尺度系统性延长，以及测得激发态频率红移，这在复杂反应坐标中最为明显。这些结果详细描述了在完全光化学转化期间液体环境对电子和结构动力学的影响。

附：英文原文

Title: Different timescales during ultrafast stilbene isomerization in the gas and liquid phases revealed using time-resolved photoelectron spectroscopy

Author: Wang, Chuncheng, Waters, Max D. J., Zhang, Pengju, Suchan, Ji, Svoboda, Vt, Luu, Tran Trung, Perry, Conaill, Yin, Zhong, Slavek, Petr, Wrner, Hans Jakob

Issue&Volume: 2022-08-11

Abstract: Directly contrasting ultrafast excited-state dynamics in the gas and liquid phases is crucial to understanding the influence of complex environments. Previous studies have often relied on different spectroscopic observables, rendering direct comparisons challenging. Here, we apply extreme-ultraviolet time-resolved photoelectron spectroscopy to both gaseous and liquid cis-stilbene, revealing the coupled electronic and nuclear dynamics that underlie its isomerization. Our measurements track the excited-state wave packets from excitation along the complete reaction path to the final products. We observe coherent excited-state vibrational dynamics in both phases of matter that persist to the final products, enabling the characterization of the branching space of the S1–S0 conical intersection. We observe a systematic lengthening of the relaxation timescales in the liquid phase and a red shift of the measured excited-state frequencies that is most pronounced for the complex reaction coordinate. These results characterize in detail the influence of the liquid environment on both electronic and structural dynamics during a complete photochemical transformation.

DOI: 10.1038/s41557-022-01012-0

Source: https://www.nature.com/articles/s41557-022-01012-0