Discovery of the acetyl cation, CH3CO+, in space and in the laboratory
| Autor: | Cernicharo, J., Cabezas, C., Bailleux, S., Margules, L., Motiyenko, R., Zou, L., Endo, Y., Bermudez, C., Agundez, M., Marcelino, N., Lefloch, B., Tercero, B., de Vicente, P. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | A&A 646, L7 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202040076 |
| Popis: | Using the Yebes 40m and IRAM 30m radiotelescopes, we detected two series of harmonically related lines in space that can be fitted to a symmetric rotor. The lines have been seen towards the cold dense cores TMC-1, L483, L1527, and L1544. High level of theory ab initio calculations indicate that the best possible candidate is the acetyl cation, CH3CO+, which is the most stable product resulting from the protonation of ketene. We have produced this species in the laboratory and observed its rotational transitions Ju = 10 up to Ju = 27. Hence, we report the discovery of CH3CO+ in space based on our observations, theoretical calculations, and laboratory experiments. The derived rotational and distortion constants allow us to predict the spectrum of CH3CO+ with high accuracy up to 500 GHz. We derive an abundance ratio N(H2CCO)/N(CH3CO+) = 44. The high abundance of the protonated form of H2CCO is due to the high proton affinity of the neutral species. The other isomer, H2CCOH+, is found to be 178.9 kJ/mol above CH3CO+. The observed intensity ratio between the K=0 and K=1 lines, 2.2, strongly suggests that the A and E symmetry states have suffered interconversion processes due to collisions with H and/or H2, or during their formation through the reaction of H3+ with H2CCO. Comment: Accepted for publication in A&A Letters |
| Databáze: | arXiv |
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