Photodissociation dynamics of SO2 between 193 and 201 nm

Zijie Luo; Zhaoxue Zhang; Shuaikang Yang; Yarui Zhao; Zhenxing Li; Zhigang He; Yao Chang; Li Che; Kaijun Yuan; Xueming Yang

doi:10.1063/5.0157095

Photodissociation dynamics of SO2 between 193 and 201 nm

J Chem Phys. 2023 Jul 14;159(2):024307. doi: 10.1063/5.0157095.

Authors

Zijie Luo^{1

2}, Zhaoxue Zhang², Shuaikang Yang², Yarui Zhao², Zhenxing Li², Zhigang He², Yao Chang², Li Che³, Kaijun Yuan^{2

4

5}, Xueming Yang^{2

4

6}

Affiliations

¹ Marine Engineering College, Dalian Maritime University, Liaoning 116026, China.
² State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
³ Department of Physics, School of Science, Dalian Maritime University, Dalian 116026, China.
⁴ Hefei National Laboratory, Hefei 230088, China.
⁵ University of Chinese Academy of Sciences, Beijing 100049, China.
⁶ Department of Chemistry and Center for Advanced Light Source Research, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.

PMID: 37439466
DOI: 10.1063/5.0157095

Abstract

The nonadiabatic interactions between the C̃ state and neighboring electronic states of SO2 have attracted much attention; however, the predissociation mechanisms are not yet completely understood. In this work, the predissociation dynamics of SO2 via its C̃ state have been investigated at λ = 193-201 nm by using the time-sliced velocity map ion imaging technique. The translational energy distributions and the branching ratios of the O(3PJ=2,1,0) spin-orbit products at six photolysis wavelengths have been acquired. The SO(3Σ-) product population gradually decreases in v = 0 and increases in v = 2 as the photolysis wavelength decreases. The branching ratios of O(3P J=2,1,0) products are almost similar at most wavelengths, except at 194.8 nm. Our data suggest that the predissociation between 193 and 201 nm is via an avoided crossing between the C̃ state and the repulsive triplet 23A' state. The state-to-state dynamical pictures shown in this work provide a rigorous test of the potential energy surfaces (PESs) of the SO2 and the nonadiabatic couplings between these PESs.