N. Marcelino, M. Agúndez, B. Tercero, C. Cabezas, C. Bermúdez, J. D. Gallego, P. de Vicente, and J. Cernicharo,
reported on the
Tentative Detection of HC₅NH⁺ in TMC-1
Astron Astrophys. 643, Art. No. L6 (2020).
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 HC₅NH⁺ as the most likely carrier of these lines. The abundance ratio of HC₅N to HC₅NH⁺ is ~240, very similar to that of HC₃N to HC₃NH⁺, 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 NC₄NH⁺. But with the detection of the latter, this has been settled.

Contributor(s): H. S. P. Müller 10, 2020; 03, 2022; 12, 2022