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Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN
- Source :
- A&A 676, L5 (2023)
- Publication Year :
- 2023
-
Abstract
- We report the first laboratory and interstellar detection of the alpha-cyano vinyl radical (H2CCCN). This species was produced in the laboratory by an electric discharge of a gas mixture of vinyl cyanide, CH2CHCN, and Ne, and its rotational spectrum was characterized using a Balle-Flygare narrowband-type Fourier-transform microwave spectrometer operating in the frequency region of 8-40 GHz. The observed spectrum shows a complex structure due to tunneling splittings between two torsional sublevels of the ground vibronic state, 0+ and 0-, derived from a large-amplitude inversion motion. In addition, the presence of two equivalent hydrogen nuclei makes necessary to discern between ortho- and para-H2CCCN. A least squares analysis reproduces the observed transition frequencies with a standard deviation of ca. 3 kHz. Using the laboratory predictions, this radical is detected in the cold dark cloud TMC-1 using the Yebes 40m telescope and the QUIJOTE line survey. The 404-303 and 505-404 rotational transitions, composed of several hyperfine components, were observed in the 31.0-50.4 GHz range. Adopting a rotational temperature of 6K we derive a column density of (1.4+/-0.2)e11 cm-2 and (1.1+/-0.2)e11 cm-2 for ortho-H2CCCN and para-H2CCCN, respectively. The reactions C + CH3CN, and perhaps also N + CH2CCH, emerge as the most likely routes to H2CCCN in TMC-1.<br />Comment: Accepted for publication in A&A Letters on 18/07/2023
- Subjects :
- Astrophysics - Astrophysics of Galaxies
Subjects
Details
- Database :
- arXiv
- Journal :
- A&A 676, L5 (2023)
- Publication Type :
- Report
- Accession number :
- edsarx.2307.09127
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1051/0004-6361/202347385