Advancing spectroscopic understanding of HOCS$^+$: Laboratory investigations and astronomical implications
| Autor: | Lattanzi, Valerio, Sanz-Novo, Miguel, Rivilla, Víctor M., Araki, Mitsunori, Bunn, Hayley A, Martín-Pintado, Jesús, Jiménez-Serra, Izaskun, Caselli, Paola |
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| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | A&A 689, A260 (2024) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/202451518 |
| Popis: | Sulphur-bearing species play crucial roles in interstellar chemistry, yet their precise characterisation remains challenging. Here, we present laboratory experiments aimed at extending the high-resolution spectroscopy of protonated carbonyl sulphide (HOCS$^+$), a recently detected molecular ion in space. Using a frequency-modulated free-space absorption spectrometer, we detected rotational transitions of HOCS$^+$ in an extended negative glow discharge with a mixture of H$_2$ and OCS, extending the high-resolution rotational characterisation of the cation well into the millimetre wave region (200-370 GHz). Comparisons with prior measurements and quantum chemical calculations revealed an overall agreement in the spectroscopic parameters. With the new spectroscopic dataset in hand, we re-investigated the observations of HOCS$^+$ towards G+0.693-0.027, which were initially based solely on K$_a$ = 0 lines contaminated by HNC$^{34}$S. This re-investigation enabled the detection of weak K$_a$ = 0 transitions, free from HNC$^{34}$S contamination. Our high-resolution spectroscopic characterisation also provides valuable insights for future millimetre and submillimetre astronomical observations of these species in different interstellar environments. In particular, the new high-resolution catalogue will facilitate the search for this cation in cold dark clouds, where very narrow line widths are typically observed. Comment: 9 pages, 3 figures, and 3 tables. Accepted for publication in Astronomy & Astrophysics |
| Databáze: | arXiv |
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