Issue |
A&A
Volume 516, June-July 2010
|
|
---|---|---|
Article Number | L4 | |
Number of page(s) | 3 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361/201014946 | |
Published online | 22 June 2010 |
Letter to the Editor
Submillimeter-wave spectrum of CH2D+
Department of Chemistry and Department of Physics and Astronomy, University of Waterloo,
200 University Avenue West, Waterloo, ON, N2L 3G1, Canada e-mail: tamano@uwaterloo.ca
Received:
6
May
2010
Accepted:
17
May
2010
Aims. Recently a tentative identification of CH2D+ in interstellar space has been reported. To facilitate astronomical identifications, laboratory measurements of precise rest frequencies for the rotational lines of CH2D+ should be carried out.
Methods. A submillimeter-wave spectrometer is used for detection of CH2D+. The CH2D+ ion is generated in an extended negative glow discharge operated at liquid nitrogen temperature. The optimum gas mixture is found to be CH4 (~3 mTorr), CD4 (~1 mTorr), and H2 (~2 mTorr) in helium buffer.
Results. Four rotational lines have been detected in the frequency range of 280–890 GHz. The measured frequencies agree very well within a MHz with the predictions given by Rösslein et al. from the infrared spectra.
Conclusions. Two rotational lines of this ion have been tentatively identified toward Ori IRc2. The rest frequencies obtained here should facilitate identifications and analysis of astronomical spectra.
Key words: molecular data / methods: laboratory / ISM: molecules / submillimeter: ISM / radio lines: ISM
© ESO, 2010
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