LABORATORY AND ASTRONOMICAL DETECTION OF THE NEGATIVE MOLECULAR ION C$_3$N$^-$
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Date
2008
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Publisher
Ohio State University
Abstract
The negative molecular ion C$_3$N$^-$ has been detected at millimeter wavelengths in a low pressure laboratory discharge, and then with frequencies in hand in the molecular envelope of IRC+10216. Spectroscopic constants derived from laboratory measurements of 12 transitions between 97 and 378~GHz allow the rotational spectrum to be calculated well into the submillimeter-wave band. Four transitions of C$_3$N$^-$ were detected in IRC+10216 with the IRAM 30~m telescope at precisely the frequencies calculated from the laboratory measurements. The column density of C$_3$N$^-$ is 0.5\% that of C$_3$N, or approximately 20~times greater than C$_4$H$^-$ relative to C$_4$H. The C$_3$N$^-$ abundance in IRC+10216 is compared with chemical model calculations,}, 210 (1997); E.~Herbst and Y.~Osamura, Astrophys. J., in press (2008).} and observations in TMC--1 with the NRAO 100~m Green Bank Telescope (GBT) are discussed. The fairly high concentration of C$_3$N$^-$ achieved in the laboratory implies that other molecular anions containing the CN group may be within reach.
Description
S. Petrie and E. Herbst, Astrophys. J. Lett. 491
Author Institution: Harvard-Smithsonian Center for Astrophysics; and School of Engineering and Applied Sciences; Harvard University, Cambridge, MA 02138; Department of Molecular and Infrared Astrophysics, Instituto de Estructura de la Materia, CSIC; 28006 Madrid, Spain; Insitut de Radioastronomie Millim{e}trique, 38406 St. Martin d'H{e}res; and; LERMA/Ecole Normale Superieure, 75231 Paris, France
Author Institution: Harvard-Smithsonian Center for Astrophysics; and School of Engineering and Applied Sciences; Harvard University, Cambridge, MA 02138; Department of Molecular and Infrared Astrophysics, Instituto de Estructura de la Materia, CSIC; 28006 Madrid, Spain; Insitut de Radioastronomie Millim{e}trique, 38406 St. Martin d'H{e}res; and; LERMA/Ecole Normale Superieure, 75231 Paris, France