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UV + VUV double-resonance studies of autoionizing Rydberg states of the hydroxyl radical.
- Source :
-
Journal of Chemical Physics . 2016, Vol. 144 Issue 18, p1-8. 8p. 1 Chart, 6 Graphs. - Publication Year :
- 2016
-
Abstract
- The hydroxyl radical (OH) is a key oxidant in atmospheric and combustion chemistry. Recently, a sensitive and state-selective ionization method has been developed for detection of the OH radical that utilizes UV excitation on the A²Σ+-X²π transition followed by fixed 118 nm vacuum ultraviolet (VUV) radiation to access autoionizing Rydberg states [J. M. Beames et al., J. Chem. Phys. 134, 241102 (2011)]. The present study uses tunable VUV radiation generated by four-wave mixing to examine the origin of the enhanced ionization efficiency observed for OH radicals prepared in specific A²Σ+ intermediate levels. The enhancement is shown to arise from resonant excitation to distinct rotational and fine structure levels of two newly identified ²π Rydberg states with an A³π cationic core and a 3d electron followed by ionization. Spectroscopic constants are derived and effects due to uncoupling of the Rydberg electron are revealed for the OH ²π Rydberg states. The linewidths indicate a Rydberg state lifetime due to autoionization on the order of a picosecond. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 144
- Issue :
- 18
- Database :
- Academic Search Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 115426284
- Full Text :
- https://doi.org/10.1063/1.4948640