The photodissociation dynamics of small (H2O)n+ (n=2–5) clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer. Time-of-flight mass spectra and images of ionic photofragments are recorded. (H2O)2+ clusters dissociate to yield H3O+ and H2O+ photofragments, indicating the presence of both proton-transferred (H3O+-OH) and hemibonded (H2O-OH2)+ structures for the dimer cluster. (H2O)n+ (n=3–5) clusters prevailingly dissociate to the H+(H2O)n–2, …,1 photofragments by losing both of OH and H2O components, and the (H2O)5+ cluster shows an additional channel to produce H+(H2O)4 by only losing OH. The former suggests the (H2O)n–2H3O+OH structures for the (H2O)n+ (n=3–5) clusters, while the latter suggests in (H2O)5+ that, the H3O+ core and OH are separated by H2O. The results elucidate the structure progresses of small (H2O)n+ clusters. The experimental images yield negative and small values for the anisotropy parameters of photofragments, indicating that (H2O)n+ (n=2–5) clusters undergo vertical electronic transitions upon photon absorption followed by slow dissociation, and lead to highly internally excited photofragments.
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April 2024
Research Article|
April 01 2024
Photodissociation studies on (H2O)n+(n=2–5) clusters at 308 nm†
Special Collection:
In Memory of Prof. Qihe Zhu on the occasion of his 100th Anniversary
Chin. J. Chem. Phys. 37, 279–285 (2024)
Article history
Received:
October 26 2023
Accepted:
November 27 2023
Citation
Yunxiao ZhaoGaoming HuYouqing LiYang ChenDongfeng Zhao; Photodissociation studies on (H2O)n+(n=2–5) clusters at 308 nm. Chin. J. Chem. Phys. 1 April 2024; 37 (2): 279–285. https://doi.org/10.1063/1674-0068/cjcp2310103
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