Inner-valence photoionization of O({sup 1}D): Experimental evidence for the 2s{sup 2}2p{sup 4}({sup 1}D){yields}2s{sup 1}2p{sup 5}({sup 1}P) transition
- Physikalische und Theoretische Chemie, Freie Universitaet Berlin, Takustr. 3, 14195 Berlin (Germany)
Photoionization and autoionization of electronically excited atomic oxygen O({sup 1}D) are investigated in the energy range between 12 and 26 eV using tunable laser-produced plasma radiation in combination with time-of-flight mass spectrometry. A broad, asymmetric, and intense feature is observed that is peaking at 20.53{+-}0.05 eV. It is assigned to the 2s{sup 2}2p{sup 4}({sup 1}D){yields}2s{sup 1}2p{sup 5}({sup 1}P) transition, which subsequently autoionizes by a Coster-Kronig transition, as predicted by the previous theoretical work [K. L. Bell et al., J. Phys. B 22, 3197 (1989)]. Specifically, the energy of the unperturbed transition occurs at 20.35{+-}0.07 eV. Its shape is described by a Fano profile revealing a q parameter of 4.25{+-}0.8 and a width of {gamma}=2.2{+-}0.15 eV. Absolute photoionization cross section {sigma} is derived, yielding {sigma}=22.5{+-}2.3 Mb at the maximum of the resonance. In addition, weak contributions to the O({sup 1}D) yield from dissociative ionization originating from molecular singlet oxygen [O{sub 2}({sup 1}{delta}{sub g})] are identified as well. Possible applications of the 2s{sup 2}2p{sup 4}({sup 1}D){yields}2s{sup 1}2p{sup 5}({sup 1}P) transition as a state-selective and sensitive probe of excited oxygen in combination with photoionization mass spectrometry are briefly discussed.
- OSTI ID:
- 21024799
- Journal Information:
- Journal of Chemical Physics, Vol. 128, Issue 7; Other Information: DOI: 10.1063/1.2830232; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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