Volume 565, May 2014
|Number of page(s)||6|
|Section||Atomic, molecular, and nuclear data|
|Published online||13 May 2014|
Accurate rest-frequencies of ketenimine (CH2CNH) at submillimetre wavelength⋆
Dipartimento di Chimica “G. Ciamician”Università di Bologna,
via F. Selmi 2,
e-mail: firstname.lastname@example.org; email@example.com
2 Centro de Astronomia e Astrofísica, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
Accepted: 20 March 2014
Context. Imine compounds are thought to have a role in the interstellar formation of complex organic species, including pre-biotic molecules. Ketenimine (CH2CNH) is one of the four imines discovered in space. It was identified in Sgr B2(N-LMH) through the detection of three rotational lines in absorption.
Aims. We present an extensive laboratory study of the ground-state rotational spectrum of CH2CNH at submillimetre wavelengths, aimed at obtaining accurate rest-frequencies for radio-astronomical searches.
Methods. The investigation was carried out using a source-modulation microwave spectrometer equipped with a cell that is coupled to a pyrolysis apparatus working at 1000°. The spectrum was recorded in the frequency range 80–620 GHz with the detection of 150 transitions.
Results. The newly measured transition frequencies were analysed with previously available microwave and far-infrared data, yielding accurate rotational constants of CH2CNH, the complete sets of quartic and sextic centrifugal distortion constants, and three octic constants. Several transitions exhibit a hyperfine structure due to the quadrupole and spin-rotation couplings of the 14N nucleus, which were accounted for in the analysis.
Conclusions. The determined spectroscopic constants allowed for the computation of a list of highly accurate rest-frequencies for astrophysical purposes in the submillimetre and THz region with 1σ uncertainties that are lower than 0.1 km s-1 in radial equivalent velocity.
Key words: molecular data / methods: laboratory: molecular / techniques: spectroscopic / radio lines: ISM
Full Tables 1 and 3 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A66
© ESO, 2014
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