%0 Journal Article
%T Detection of C$_{3}$ in Diffuse Interstellar Clouds
%A J. P. Maier
%A N. M. Lakin
%A G. A. H. Walker
%A D. A. Bohlender
%J Physics
%D 2001
%I arXiv
%R 10.1086/320668
%X The smallest polyatomic carbon chain, C$_{3}$, has been identified in interstellar clouds (A$_{v}\sim$1 mag) towards $\zeta$ Ophiuchi, 20 Aquilae, and $\zeta$ Persei by detection of the origin band in its $A^{1}\Pi_{u}-X^{1}\Sigma^{+}_{g}$ electronic transition, near 4052\AA. Individual rotational lines were resolved up to $J$=30 enabling the rotational level column densities and temperature distributions to be determined. The inferred limits for the total column densities ($\sim$1 to 2$\times10^{12}$ cm$^{-2}$) offer a strong incentive to laboratory and astrophysical searches for the longer carbon chains. Concurrent searches for C$_2^{+}$, C$_2^{-}$ and C$_3^{-}$ were negative but provide sensitive estimates for their maximum column densities.
%U http://arxiv.org/abs/astro-ph/0102449v1