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http://hdl.handle.net/20.500.12666/279
Title: | Propargylimine in the laboratory and in space: millimetre-wave spectroscopy and its first detection in the ISM |
Authors: | Bizzocchi, L. Prudenzano, D. Rivilla, V. M. Pietropolli Charmet, A. Giuliano, B. M. Caselli, P. Martín Pintado, J. Jiménez Serra, I. Martín, S. Requena Torres, M. A. Rico Villas, F. Guillemin, J. C. |
Keywords: | Molecular data;Methods: laboratory: molecular;Methods: observational;Techniques: spectroscopic;ISM: clouds;ISM: molecules |
Issue Date: | 20-Aug-2020 |
Publisher: | EDP Sciences |
DOI: | 10.1051/0004-6361/202038083 |
Published version: | https://www.aanda.org/articles/aa/full_html/2020/08/aa38083-20/aa38083-20.html |
Citation: | Astronomy and Astrophysics 640: A98(2020) |
Abstract: | Context. Small imines containing up to three carbon atoms are present in the interstellar medium (ISM). As alkynyl compounds are abundant in this medium, propargylimine (2-propyn-1-imine, HC ≡C−CH =NH) thus represents a promising candidate for a new interstellar detection. Aims. The goal of the present work is to perform a comprehensive laboratory investigation of the rotational spectrum of propargylimine in its ground vibrational state in order to obtain a highly precise set of rest frequencies and to search for it in space. Methods. The rotational spectra of E and Z geometrical isomers of propargylimine have been recorded in the laboratory in the 83–500 GHz frequency interval. The measurements have been performed using a source-modulation millimetre-wave spectrometer equipped with a pyrolysis system for the production of unstable species. High-level ab initio calculations were performed to assist the analysis and to obtain reliable estimates for an extended set of spectroscopic quantities. We searched for propargylimine at 3 mm and 2 mm in the spectral survey of the quiescent giant molecular cloud G+0.693-0.027 located in the central molecular zone, close to the Galactic centre. Results. About 1000 rotational transitions have been recorded for the E- and Z-propargylimine, in the laboratory. These new data have enabled the determination of a very accurate set of spectroscopic parameters including rotational, quartic, and sextic centrifugal distortion constants. The improved spectral data allowed us to perform a successful search for this new imine in the G+0.693-0.027 molecular cloud. Eighteen lines of Z-propargylimine were detected at level >2.5σ, resulting in a column-density estimate of N = (0.24 ± 0.02) × 1014 cm−2. An upper limit was retrieved for the higher energy E isomer, which was not detected in the data. The fractional abundance (with respect to H2) derived for Z-propargylimine is 1.8 × 10−10. We discuss the possible formation routes by comparing the derived abundance with those measured in the source for possible chemical precursors. |
Description: | Table of the measured laboratory frequencies is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A98 |
URI: | http://hdl.handle.net/20.500.12666/279 |
E-ISSN: | 1432-0746 |
ISSN: | 0004-6361 |
Appears in Collections: | (CAB) Artículos |
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File | Description | Size | Format | |
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Propargylimine in the laboratory and in space- millimetre wave spectroscopy and its first detection in the ISM.pdf | 1 MB | Adobe PDF | View/Open |
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