@article{0004-637X-677-2-1132,
  author={P. Thaddeus and C. A. Gottlieb and H. Gupta and S. Brünken and M. C. McCarthy and M. Agúndez and M. Guélin and J. Cernicharo},
  title={Laboratory and Astronomical Detection of the Negative Molecular Ion C3N−},
  journal={The Astrophysical Journal},
  volume={677},
  number={2},
  pages={1132},
  url={http://stacks.iop.org/0004-637X/677/i=2/a=1132},
  year={2008},
  abstract={The negative molecular ion C 3 N − has been detected at millimeter wavelengths in a low-pressure laboratory discharge, and then with frequencies derived from the laboratory data in the molecular envelope of IRC+10216. Spectroscopic constants derived from laboratory measurements of 12 transitions between 97 and 378 GHz allow the rotational spectrum to be calculated well into the submillimeter-wave band to 0.03 km s −1 or better in equivalent radial velocity. Four transitions of C 3 N − were detected in IRC+10216 with the IRAM 30 m telescope at precisely the frequencies calculated from the laboratory measurements. The column density of C 3 N − is 0.5% that of C 3 N, or approximately 20 times greater than that of C 4 H − relative to C 4 H. The C 3 N − abundance in IRC+10216 is compared with a chemical model calculation by Petrie & Herbst. An upper limit in TMC-1 for C 3 N − relative to C 3 N (<0.8%) and a limit for C 4 H − relative to C 4 H (<0.004%) that is 5 times lower than that found in IRC+10216, were obtained from observations with the NRAO 100 m Green Bank Telescope (GBT). The fairly high concentration of C 3 N − achieved in the laboratory implies that other molecular anions containing the CN group may be within reach.}
}