A new spectroscopic window on hydroxyl radicals using UV + VUV resonant ionization

Beames, J.M., Liu, F., Lester, M.I. and Murray, C. (2011) A new spectroscopic window on hydroxyl radicals using UV + VUV resonant ionization. Journal of Chemical Physics, 134(24), p. 241102. (doi: 10.1063/1.3608061)

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Publisher's URL: http://dx.doi.org/10.1063/1.3608061


A 1 + 1′ multiphoton ionization (MPI) detection scheme for OH radicals is presented. The spectroscopic approach combines initial excitation on the well-characterized A<sup>2</sup>Σ+–X<sup>2</sup>Π band system with vacuum ultraviolet (VUV) ionization via autoionizing Rydberg states that converge on the OH<sup>+</sup> A<sup>3</sup>Π ion state. Jet-cooled MPI spectra on the (1,0) and (2,0) bands show anomalous rotational line intensities, while initial excitation on the (0,0) band does not lead to detectable OH<sup>+</sup> ions. The onset of ionization with the (1,0) band is attributed to an energetic threshold; the combined UV + VUV photon energies are above the first member of the autoionizing (A<sup>3</sup>Π)nd Rydberg series. Comparison of the OH 1 + 1′ MPI signal with that from single photon VUV ionization of NO indicates that the cross section for photoionization from OH A<sup>2</sup>Σ+, v′ = 1 is on the order of 10<sup>−17</sup> cm<sup>2</sup>.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Murray, Dr Craig
Authors: Beames, J.M., Liu, F., Lester, M.I., and Murray, C.
Subjects:Q Science > QD Chemistry
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Journal of Chemical Physics
ISSN (Online):1089-7690
Published Online:24 June 2011

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