Karashima Shutaro, Humeniuk Alexander, Glover William J, Suzuki Toshinori
Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto 606-8502, Japan.
NYU Shanghai, 1555 Century Avenue, Shanghai 200122, China.
J Phys Chem A. 2022 Jun 23;126(24):3873-3879. doi: 10.1021/acs.jpca.2c02468. Epub 2022 Jun 13.
The photoisomerization of isolated ethylene (ethene) was observed in real time from the Franck-Condon region in the ππ* state to ground-state products using time-resolved photoelectron spectroscopy with extreme ultraviolet (EUV, 21.7 eV) probe pulses. A combination of filamentation four-wave mixing and high-order harmonic generation was employed to obtain a temporal resolution of 31 ± 2 fs. The nuclear wave packet created by a 160 nm pump pulse accesses C═C twisted geometries within 10 fs, and the population transfer from the excited to the ground state occurs within the next 20-30 fs. Formation of vibrationally highly excited ground-state molecules was observed in less than 45 fs, and they decayed with two time constants of 0.87 and >5 ps. The interpretation of the photoelectron spectra is supported by vertical ionization energies calculated using XMS-CASPT2 along geodesically interpolated reaction paths from the Franck-Condon region to the products.
利用极紫外（EUV，21.7 eV）探测脉冲的时间分辨光电子能谱，从ππ*态的弗兰克 - 康登区域到基态产物实时观测了孤立乙烯（ethene）的光异构化。采用丝状四波混频和高次谐波产生相结合的方法，获得了31±2 fs的时间分辨率。由160 nm泵浦脉冲产生的核波包在10 fs内进入C═C扭曲几何结构，并且从激发态到基态的布居转移在接下来的20 - 30 fs内发生。在不到45 fs的时间内观察到振动高度激发的基态分子的形成，并且它们以0.87和>5 ps的两个时间常数衰减。使用XMS - CASPT2沿着从弗兰克 - 康登区域到产物的测地线插值反应路径计算的垂直电离能，支持了对光电子能谱的解释。
