Infrared spectroscopy of the NO3 radical from 2000 to 3000[U+202F]cm-1

Kentarou Kawaguchi, Ryuji Fujimori, Jian Tang, Takashi Ishiwata

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2 Citations (Scopus)


The present paper reports high-resolution spectroscopic study of the 14NO3 radical in the 2000-3000[U+202F]cm-1 region, where eight E'-A 2' bands from the ground state are observed. Three bands at 2206, 2246, and 2377[U+202F]cm-1 are analyzed for the first time, and assigned to the ν 1 +3ν 4, 2ν 2 +2ν 4, and ν 3 +3ν 4 bands, respectively. Bands at 2024, 2155, 2518, and 2585[U+202F]cm-1 are reassigned to the ν 1 + ν 3, 2ν 3, ν 1 + ν 3 + ν 4, and 2ν 3 + ν 4 bands, respectively, by adopting the new ν 3 vibrational frequency of 1055[U+202F]cm-1 lower than the previous ν 3 =1492[U+202F]cm-1. The band at 2902[U+202F]cm-1 is observed for the first time and assigned to the ν 1 + ν 3 +2ν 4 band which is the ν 1 combined band with the 1927[U+202F]cm-1 band. Band intensities observed in the 2000-3000[U+202F]cm-1 region are attributed to the intensity borrowing from the B˜2E'-X˜2A2' electronic transition through the vibronic interaction. Although the ν 3 fundamental band has not been observed due to the cancelation of vibrational intensity and borrowed intensity, the 2ν 3 band becomes stronger than ν 3 by a factor of more than 50. Perturbation effects are recognized for the bands observed except for the 2206[U+202F]cm-1 and 2377[U+202F]cm-1 bands, and are analyzed by taking into account the Coriolis interaction in the most cases. However, the 2024[U+202F]cm-1 band is free from the Coriolis interaction, and the v1-v3 interaction is incorporated in the analysis, leading to the 2ν 1 frequency of 2008.8[U+202F]cm-1, which is close to the energy value of 2010[U+202F]cm-1 observed by a laser induced fluorescence study.

Original languageEnglish
JournalJournal of Molecular Spectroscopy
Publication statusAccepted/In press - 2017


  • IR spectroscopy
  • Low ν frequency
  • Nitrate radical
  • Vibronic interaction
  • ν + ν and 2ν vibration

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Spectroscopy
  • Physical and Theoretical Chemistry

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