@article{1538-4357-592-2-L91,
  author={M. C. McCarthy and P. Thaddeus},
  title={The Radio Spectrum of Si3},
  journal={The Astrophysical Journal Letters},
  volume={592},
  number={2},
  pages={L91},
  url={http://stacks.iop.org/1538-4357/592/i=2/a=L91},
  year={2003},
  abstract={The silicon trimer Si 3 and several of its rare isotopic species have been detected in the laboratory, and the frequencies of 66 rotational transitions in the range 5-42 GHz have been measured to a few parts in 10 7 . The most intense radio lines can be calculated from the derived spectroscopic constants to better than 3 km s -1 in equivalent radial velocity up to frequencies of 50 GHz, adequate for a deep search in the best astronomical sources; above that frequency the uncertainties increase to of the order of 20 km s -1 at 160 GHz, which is still sufficient for a deep search in a wide-line source such as IRC +10216.}
}