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| molecules:ism:butadiynyliminomethylium [2020/10/29 09:43] – created mueller | molecules:ism:butadiynyliminomethylium [2022/12/27 14:14] (current) – mueller |
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| ===== Detection of Butadiynyliminomethylium, HC5N+, in the ISM ===== | ===== Detection of Protonated HC<sub>5</sub>N in the ISM ===== |
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| N. Marcelino, M. Agúndez, B. Tercero, C. Cabezas, C. Bermúdez, J. D. Gallego, P. de Vicente, and J. Cernicharo, \\ | N. Marcelino, M. Agúndez, B. Tercero, C. Cabezas, C. Bermúdez, J. D. Gallego, P. de Vicente, and J. Cernicharo, \\ |
| **[[https://doi.org/10.1051/0004-6361/202039251|Tentative Detection of HC<sub>5</sub>NH<sup>+</sup> in TMC-1]]**\\ | **[[https://doi.org/10.1051/0004-6361/202039251|Tentative Detection of HC<sub>5</sub>NH<sup>+</sup> in TMC-1]]**\\ |
| //Astron Astrophys.// **643**, Art. No. L6 (2020).\\ | //Astron Astrophys.// **643**, Art. No. L6 (2020).\\ |
| Two transitions, //J"// = 3 and 4 near 35.7 and 44.6 GHz, of a new, unknown molecule were detected in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope. Subsequently, two additional transitions, //J"// = 9 and 10 near 89.2 and 98.1 GHz, were identified in data from an older IRAM 30 m line survey of TMC-1. Laboratory measurements confirmed the identity of the molecule as ethynyloxomethylium.\\ | Seven transitions, from //J"// = 12 to 18 between about 33.7 and 49.2 GHz, of a new, unknown molecule were detected in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope. Quantum-chemical calculations yielded HC<sub>5</sub>NH<sup>+</sup> as the most likely carrier of these lines. The abundance ratio of HC<sub>5</sub>N to HC<sub>5</sub>NH<sup>+</sup> is ~240, very similar to that of HC<sub>3</sub>N to HC<sub>3</sub>NH<sup>+</sup>, which can be seen as additional support for the identification. The "tentative" in the title refers to the identification of the carrier. The spectroscopic parameters are very similar to those of **[[molecules:ism:NC4NH-plus|NC]]<sub>4</sub>NH<sup>+</sup>**. But with the detection of the latter, this has been settled.\\ |
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| The abundance ratio of C<sub>3</sub>O to HC<sub>3</sub>O<sup>+</sup> is ~7, extremely low, whereas astrochemical modeling with protonation of C<sub>3</sub>O as dominant source of HC<sub>3</sub>O<sup>+</sup> yielded a ratio of ~500 at steady state. The abundance ratio of C<sub>3</sub>S to HC<sub>3</sub>S<sup>+</sup> should be even lower because of the larger proton affinity of C<sub>3</sub>S compared to C<sub>3</sub>O. However, HC<sub>3</sub>S<sup>+</sup> was not detected, and the C<sub>3</sub>S to HC<sub>3</sub>S<sup>+</sup> ratio was evaluated to be larger than 25, strongly suggesting that protonation of C<sub>3</sub>O is not an important source of HC<sub>3</sub>O<sup>+</sup> in TMC-1.\\ | |
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| Contributor(s): H. S. P. Müller 10, 2020 | Contributor(s): H. S. P. Müller 10, 2020; 03, 2022; 12, 2022 |
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