Zhao Yarui, Chen Junjie, Luo Zijie, Chang Yao, Yang Jiayue, Zhang Weiqing, Wu Guorong, Crane Stuart W, Hansen Christopher S, Ding Hongbin, An Feng, Hu Xixi, Xie Daiqian, Ashfold Michael N R, Yuan Kaijun, Yang Xueming
School of Physics, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology Dalian 116024 China.
State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 China
Chem Sci. 2023 Feb 14;14(10):2501-2517. doi: 10.1039/d2sc06988a. eCollection 2023 Mar 8.
Photochemistry plays a significant role in shaping the chemical reaction network in the solar nebula and interstellar clouds. However, even in a simple triatomic molecule photodissociation, determination of all fragmentation processes is yet to be achieved. In this work, we present a comprehensive study of the photochemistry of HS, derived from cutting-edge translational spectroscopy measurements of the H, S(D) and S(S) atom products formed by photolysis at wavelengths across the range 155-120 nm. The results provide detailed insights into the energy disposal in the SH(), SH() and H co-fragments, and the atomisation routes leading to two H atoms along with S(P) and S(D) atoms. Theoretical calculations allow the dynamics of all fragmentation processes, especially the bimodal internal energy distributions in the diatomic products, to be rationalised in terms of non-adiabatic transitions between potential energy surfaces of both A' and A'' symmetry. The comprehensive picture of the wavelength-dependent (or vibronic state-dependent) photofragmentation behaviour of HS will serve as a text-book example illustrating the importance of non-Born-Oppenheimer effects in molecular photochemistry, and the findings should be incorporated in future astrochemical modelling.
光化学在塑造太阳星云和星际云中的化学反应网络方面发挥着重要作用。然而，即使在简单的三原子分子光解离过程中，确定所有的碎片化过程仍未实现。在这项工作中，我们通过对在155 - 120 nm波长范围内光解产生的H、S(D)和S(S)原子产物进行前沿的平移光谱测量，对HS的光化学进行了全面研究。结果详细揭示了SH( )、SH( )和H共碎片中的能量分布，以及导致两个H原子与S(P)和S(D)原子的原子化途径。理论计算使所有碎片化过程的动力学，特别是双原子产物中的双峰内能分布，能够根据A'和A''对称的势能面之间的非绝热跃迁得到合理解释。HS波长依赖（或振动态依赖）的光碎片化行为的全面图景将成为一个教科书式的例子，说明非玻恩 - 奥本海默效应在分子光化学中的重要性，并且这些发现应纳入未来的天体化学建模中。
