Photodissociation dynamics of H 2 O and D 2 O via the D[combining tilde]( 1 A 1 ) electronic state

• Published in: Physical chemistry chemical physics : PCCP 2020-02, Vol.22 (8), p.4379-4386
• Main Authors: Chang, Yao, Zhou, Jiami, Luo, Zijie, Chen, Zhichao, He, Zhigang, Yu, Shengrui, Che, Li, Wu, Guorong, Wang, Xingan, Yuan, Kaijun, Yang, Xueming
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c9cp05321b

Photodissociation dynamics of H O and D O via the D[combining tilde] state by one-photon excitation have been investigated using the H/D atom Rydberg tagging time-of-flight technique. The TOF spectra of the H/D-atom product in both parallel and perpendicular polarizations have been measured. Product translational energy distributions and angular distributions have been derived from TOF spectra. By simulating these distributions, quantum state distributions of the OH/OD product as well as the state-resolved angular anisotropy parameters were determined. The most important pathway of H O/D O dissociation via the D[combining tilde] state leads to highly rotationally excited OH/OD(X, v = 0) products, while vibrationally excited OH/OD products with v≥ 1 comprise only one third of the total OH/OD(X) population. The branching ratios of OH(A)/OH(X) and OD(A)/OD(X) have also been determined, 1.0/3.0 for H O at 122.12 nm and 1.0/2.2 for D O at 121.95 nm, which are reasonably consistent with the values predicted by the previous theory.