@article{1538-4357-483-2-L139,
  author={M. C. McCarthy and M. J. Travers and C. A. Gottlieb and P. Thaddeus},
  title={Laboratory Detection of the Ring-Chain Molecule C7H2},
  journal={The Astrophysical Journal Letters},
  volume={483},
  number={2},
  pages={L139},
  url={http://stacks.iop.org/1538-4357/483/i=2/a=L139},
  year={1997},
  abstract={Following the recent laboratory detection of the ring-chain carbene C 5 H 2 , we have now detected C 7 H 2 , the next longer member of the sequence formed by substituting a carbon chain for one of the hydrogen atoms of cyclic C 3 H 2 . The strongest lines, again obtained with a diacetylene-neon discharge, were roughly 15 times weaker than those of C 5 H 2 . Enough rotational lines were detected in both the normal and doubly deuterated isotopic species to be certain of the identification and to obtain the rotational and leading centrifugal distortion constants accurately enough for calculation of the entire rotational spectrum below 300 GHz to a fraction of 1 km s -1 in equivalent radial velocity. The ring chain here is calculated to be the most stable isomer of C 7 H 2 and extremely polar, so it is of considerable astronomical interest. Several other isomers of C 7 H 2 may be detectable in the laboratory and in space with present techniques.}
}