McGhee Henry G, Thompson Henry J, Thompson James, Zhang Yu, Wyatt Adam S, Springate Emma, Chapman Richard T, Horke Daniel A, Minns Russell S, Ingle Rebecca A, Parkes Michael A
Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
Phys Chem Chem Phys. 2024 Nov 20;26(45):28406-28416. doi: 10.1039/d4cp02952f.
The presence of two chlorine atoms in 1,2-dichloroethene allows for isomerization around the double bond. This isomerization can lead to rich photochemistry. We present a time-resolved pump-probe photoelectron spectroscopy measurement on both the - and - isomers of 1,2-dichloroethene. A universal XUV probe of 22.3 eV is used allowing observation of photoelectrons formed anywhere on the potential energy surface, even from the ground-state or dissociation products. Following excitation with a 200 nm pump both ultrafast excited state dynamics and product formation are observed within the time resolution of the experiment. Excited state population begins to return to the ground state on an ultrafast time scale (<70 fs) and population of products channels is observed on the same timescale. With the aid of calculations it is found that population transfer from the excited state is facilitated by vibrational modes involving C-C-H bends.
1,2 - 二氯乙烯中两个氯原子的存在使得围绕双键发生异构化成为可能。这种异构化会引发丰富的光化学现象。我们对1,2 - 二氯乙烯的顺式和反式异构体进行了时间分辨泵浦 - 探测光电子能谱测量。使用了能量为22.3 eV的通用极紫外探针，从而能够观测在势能面上任何位置形成的光电子，甚至包括基态或解离产物产生的光电子。用200 nm的泵浦光激发后，在实验的时间分辨率范围内观测到了超快激发态动力学过程和产物形成。激发态布居在超快时间尺度（<70 fs）上开始返回基态，并且在相同时间尺度上观测到了产物通道的布居。借助计算发现，涉及C - C - H弯曲的振动模式促进了激发态的布居转移。
