EDP Sciences
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Volume 464, Number 3, March IV 2007
Page(s) L33 - L36
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20066964

A&A 464, L33-L36 (2007)
DOI: 10.1051/0004-6361:20066964


Laboratory detection of the negative molecular ion CCH-

S. Brünken1, C. A. Gottlieb1, H. Gupta1, 2, M. C. McCarthy1, and P. Thaddeus1

1  Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA, and Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138, USA
    e-mail: sbruenken@cfa.harvard.edu
2  Institute for Theoretical Chemistry, Department of Chemistry and Biochemistry, The University of Texas, Austin, TX 78712, USA

(Received 19 December 2006 / Accepted 19 January 2007)

Aims.This paper reports the laboratory detection of the rotational spectrum of the acetylide anion, CCH-.
Methods.Five successive rotational transitions have been measured to high accuracy in a dc discharge with a free space millimeter-wave spectrometer in the frequency range 83-417 GHz.
Results.Precise spectroscopic constants have been obtained for CCH- and transition rest frequencies can now be calculated to better than 1 km s-1 in equivalent radial velocity far into the terahertz region, allowing for deep astronomical searches for this anion in space. The highly stable and fairly polar CCH- anion is a likely candidate for radio astronomical detection, its neutral analogue CCH being among one of the most abundant molecules in a wide variety of astrophysical sources.

Key words: line: identification -- molecular data -- astrochemistry -- methods: laboratory -- ISM: molecules -- radio lines: ISM

© ESO 2007