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Quantifying the photoionization cross section of the hydroxyl radical.
- Source :
- Journal of Chemical Physics; 4/14/2019, Vol. 150 Issue 14, pN.PAG-N.PAG, 6p, 4 Graphs
- Publication Year :
- 2019
-
Abstract
- The hydroxyl free radical, OH, is one of the most important radicals in atmospheric and interstellar chemistry, and its cation plays a role in the reactions leading to H<subscript>2</subscript>O formation. Knowledge of the photoionization efficiency of the OH radical is crucial to properly model the water photochemical cycle of atmospheres and astrophysical objects. Using a gas-phase radical source based on a single H-abstraction reaction combined with a photoelectron/photoion imaging coincidence spectrometer coupled with synchrotron radiation, we recorded the OH<superscript>+</superscript> photoion yield over the 12.6–15 eV energy range, and we set it to an absolute cross section scale using an absolute point measurement performed at 13.8 eV: σ O H i o n = 9.0 ± 2.7 Mb. The resulting cross section values differ by approximately a factor 2 from the recent measurement of Dodson et al. [J. Chem. Phys. 148, 184302 (2018)] performed with a different radical source, which is somewhat greater than the combined uncertainties of the measurements. This finding underlines the need for further investigations of this cross section. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 150
- Issue :
- 14
- Database :
- Complementary Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 135877785
- Full Text :
- https://doi.org/10.1063/1.5091966