Photofragment ion imaging in vibrational predissociation of the H2O+Ar complex ion
| Autor: | Yuji Nakashima, Mizuhiro Kominato, Keijiro Ohshimo, Yuri Ito, Fuminori Misaizu |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
010304 chemical physics Overtone Relaxation (NMR) General Physics and Astronomy 010402 general chemistry 01 natural sciences Molecular physics Dissociation (psychology) 0104 chemical sciences Rotational energy Ion Excited state 0103 physical sciences Photofragment-ion imaging medicine Physics::Chemical Physics Physical and Theoretical Chemistry medicine.symptom Astrophysics::Galaxy Astrophysics Excitation |
| Zdroj: | The Journal of Chemical Physics. 154:174301 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/5.0049609 |
| Popis: | Vibrational predissociation processes of the H2O+Ar complex ion following mid-infrared excitations of the OH stretching modes and bending overtone of the H2O+ unit were studied by photofragment ion imaging. The anisotropy parameters, β, of the angular distributions of the photofragment ions were clearly dependent on the type (branch) of rotational excitation, β > 0 for the P-branch excitations, while β < 0 for the Q-branch excitations, which were consistent with the previous theoretical predictions for the rotationally resolved optical transition of a prolate symmetric top. The translational energy distributions had a similar form, irrespective of the excitation modes. This result suggests that the prepared excited states underwent a common relaxation pathway via the bending or bending overtone state of the H2O+ unit. In addition, the available energy was preferentially distributed into the rotational energy of the H2O+ fragment ions rather than the translational energy. The mechanism of the rotational excitations of the H2O+ fragment ions was discussed based on the steric configuration of the H2O+ and Ar units at the moment of dissociation. |
| Databáze: | OpenAIRE |
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