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Title: Laboratory study of isocyanic acid ions: Rotational spectroscopy of NCO{sup −}, H{sub 2}NCO{sup +}, and HNCOH{sup +}

We report detection of protonated isocyanic acid in two isomeric forms, H{sub 2}NCO{sup +} and HNCOH{sup +}, by high-resolution spectroscopy. The two ions were first observed at centimeter wavelengths by Fourier Transform (FT) microwave spectroscopy, in a discharge through HNCO heavily diluted in hydrogen in the throat of a supersonic nozzle. Spectroscopic constants derived from the two lowest rotational transitions of both isomers agree very well with those derived from theoretical structures computed at the coupled cluster level of theory. In the same molecular beam, the fundamental rotational transition of NCO{sup −} was observed with well-resolved nitrogen quadrupole hyperfine structure. Detection of NCO{sup −} and H{sub 2}NCO{sup +} in our beam was subsequently confirmed by observation of several millimeter-wave transitions in a low pressure discharge through cyanogen and water. The spectroscopic constants of NCO{sup −} obtained earlier by infrared laser spectroscopy are in good agreement with the highly accurate constants derived here. Owing to the high abundance of HNCO in many galactic molecular sources, both ions are excellent candidates for astronomical detection in the radio band.
Authors:
; ; ;  [1] ;  [2]
  1. Harvard-Smithsonian Center for Astrophysics, and School of Engineering and Applied Sciences, Harvard University (United States)
  2. I. Physikalisches Institut Universität zu Köln, and Max-Planck-Institut für Radioastronomie (Germany)
Publication Date:
OSTI Identifier:
22390910
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1642; Journal Issue: 1; Conference: ICCMSE-2010: International Conference of Computational Methods in Sciences and Engineering 2010, Kos (Greece), 3-8 Oct 2010; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION SPECTROSCOPY; CYANOGEN; ELECTRIC DISCHARGES; FOURIER TRANSFORMATION; HYDROGEN; HYPERFINE STRUCTURE; ISOCYANATES; ISOMERS; LASER SPECTROSCOPY; MICROWAVE RADIATION; MOLECULAR BEAMS; MOLECULAR IONS; NITROGEN; WATER