@article{0067-0049-196-2-17,
  author={D. L. Kokkin and S. Brünken and K. H. Young and N. A. Patel and C. A. Gottlieb and P. Thaddeus and M. C. McCarthy},
  title={The Rotational Spectra of 29SiC2 and 30SiC2},
  journal={The Astrophysical Journal Supplement Series},
  volume={196},
  number={2},
  pages={17},
  url={http://stacks.iop.org/0067-0049/196/i=2/a=17},
  year={2011},
  abstract={The rotational spectra of 29 SiC 2 and 30 SiC 2 , two silicon isotopic species of the abundant astronomical ring 28 SiC 2 , have been characterized in the millimeter band between 140 and 360 GHz in a low pressure discharge through SiH 4 , C 2 H 2 , and Ar. Precise rotational and centrifugal distortion constants have been derived for both species by fitting a standard asymmetric top Hamiltonian to 38 a -type transitions of 29 SiC 2 and 35 of 30 SiC 2 ; the data sets include transitions up to K a = 8 and at least J = 16. With these new measurements in hand, the most intense radio transitions of both species either have been measured or can now be predicted to better than 1 km s –1 in equivalent radial velocity up to 500 GHz, more than adequate accuracy for spectral line identifications in circumstellar shells of evolved carbon stars such as IRC+10216 where SiC 2 is conspicuous. More than 10 new lines of 29 SiC 2 and 30 SiC 2 have been identified between 295 and 354 GHz in the interferometric spectral line survey of IRC+10216 with the Submillimeter Array.}
}