J. K. Anderson and L. M. Ziurys,
reported on the
Detection of CCN (X 2Πr) in IRC+10216: Constraining Carbon-chain Chemistry,
Astrophys. J. 795 Art. No. L1 (2014).
The ARO 12 m and the ARO SMT were used to detect the two Λ-doubling components each of three rotational transitions in the 2Π1/2 lower energy spin ladder: the J = 9.5 8.5, 6.5 5.5, and the 4.5 3.5 transitions near 224.45, 153.63, and 106.36 GHz in the circumstellar envelope of CW Leonis. According to the authors, the higher frequency f-components are always unblended, whereas the e-components are always partially blended. Because of its rather low abundance, ratios of about 500 : 1 : 50 were derived for CN, C2N, and C3N, and its small dipole moment, the molecule was very hard to detect.