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| molecules:ism:butadiynyliminomethylium [2020/10/29 09:43] – created mueller | molecules:ism:butadiynyliminomethylium [2022/03/25 11:18] – 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, but that may be viewed as almost definitive.\\ |
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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 |
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