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

Joseph M. Beames; Fang Liu; Marsha I. Lester; Craig Murray

doi:10.1063/1.3608061

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

Joseph M. Beames
, Fang Liu
, Marsha I. Lester^*
, Craig Murray

^*Corresponding author for this work

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

A 1 1′ multiphoton ionization (MPI) detection scheme for OH radicals is presented. The spectroscopic approach combines initial excitation on the well-characterized A²Σ⁺-X² band system with vacuum ultraviolet (VUV) ionization via autoionizing Rydberg states that converge on the OH⁺ A³ 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⁺ 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 (A³)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 A²Σ⁺, v′ 1 is on the order of 10^-17 cm².

Original language	English
Article number	241102
Journal	Journal of Chemical Physics
Volume	134
Issue number	24
DOIs	https://doi.org/10.1063/1.3608061
Publication status	Published - 28 Jun 2011

ASJC Scopus subject areas

General Physics and Astronomy
Physical and Theoretical Chemistry

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title = "Communication: A new spectroscopic window on hydroxyl radicals using UV + VUV resonant ionization",

abstract = "A 1 1′ multiphoton ionization (MPI) detection scheme for OH radicals is presented. The spectroscopic approach combines initial excitation on the well-characterized A2Σ+-X2 band system with vacuum ultraviolet (VUV) ionization via autoionizing Rydberg states that converge on the OH+ A3 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+ 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 (A3)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 A2Σ+, v′ 1 is on the order of 10-17 cm2.",

author = "Beames, \{Joseph M.\} and Fang Liu and Lester, \{Marsha I.\} and Craig Murray",

year = "2011",

month = jun,

day = "28",

doi = "10.1063/1.3608061",

language = "English",

volume = "134",

journal = "Journal of Chemical Physics",

issn = "0021-9606",

publisher = "American Institute of Physics",

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T2 - A new spectroscopic window on hydroxyl radicals using UV + VUV resonant ionization

AU - Beames, Joseph M.

AU - Liu, Fang

AU - Lester, Marsha I.

AU - Murray, Craig

PY - 2011/6/28

Y1 - 2011/6/28

N2 - A 1 1′ multiphoton ionization (MPI) detection scheme for OH radicals is presented. The spectroscopic approach combines initial excitation on the well-characterized A2Σ+-X2 band system with vacuum ultraviolet (VUV) ionization via autoionizing Rydberg states that converge on the OH+ A3 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+ 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 (A3)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 A2Σ+, v′ 1 is on the order of 10-17 cm2.

AB - A 1 1′ multiphoton ionization (MPI) detection scheme for OH radicals is presented. The spectroscopic approach combines initial excitation on the well-characterized A2Σ+-X2 band system with vacuum ultraviolet (VUV) ionization via autoionizing Rydberg states that converge on the OH+ A3 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+ 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 (A3)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 A2Σ+, v′ 1 is on the order of 10-17 cm2.

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DO - 10.1063/1.3608061

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JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

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ER -

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

Abstract

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