Laboratory and Astronomical Identification of the Negative Molecular Ion C6H-

M. C. McCarthy, C. A. Gottlieb, H. Gupta, P. Thaddeus
2006 Astrophysical Journal  
The negative molecular ion C 6 H Ϫ has been detected in the radio band in the laboratory and has been identified in the molecular envelope of IRC ϩ10216 and in the dense molecular cloud TMC-1. The spectroscopic constants derived from laboratory measurements of 17 rotational lines between 8 and 187 GHz are identical to those derived from the astronomical data, establishing unambiguously that C 6 H Ϫ is the carrier of the series of lines with rotational constant 1377 MHz first observed by K.
more » ... uchi et al. in IRC ϩ10216. The column density of C 6 H Ϫ toward both sources is 1%-5% that of neutral C 6 H. These surprisingly high abundances for a negative ion imply that if other molecular anions are similarly abundant with respect to their neutral counterparts, they may be detectable both in the laboratory at high resolution and in interstellar molecular clouds.
doi:10.1086/510238 fatcat:2t4lcatenbbr3efesk3odi6iky