1. Propargylimine in the laboratory and in space: Millimetre-wave spectroscopy and its first detection in the ISM
- Author
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Sergio Martín, Jesús Martín-Pintado, Jean-Claude Guillemin, Victor M. Rivilla, Barbara M. Giuliano, Luca Bizzocchi, Shaoshan Zeng, Andrea Pietropolli-Charmet, Paola Caselli, D. Prudenzano, M. A. Requena-Torres, Fernando Rico-Villas, Izaskun Jiménez-Serra, Bizzocchi L., Prudenzano D., Rivilla V.M., Pietropolli-Charmet A., Giuliano B.M., Caselli P., Martin-Pintado J., Jimenez-Serra I., Martin S., Requena-Torres M.A., Rico-Villas F., Zeng S., Guillemin J.-C., Max-Planck-Institut für Extraterrestrische Physik (MPE), Istituto Nazionale di Astrofisica (INAF), University of Ca’ Foscari [Venice, Italy], Spanish National Research Council (CSIC), European Southern Observatory (ESO), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Johns Hopkins University (JHU), Towson University [Towson, MD, United States], University of Maryland System, RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), University Ca Foscari Venezia, CINECACINECA, Italy [HP10C2QE6F], European Union European Union (EU) [664931], Spanish FEDER [ESP2017-86582-C4-1-R], State Research Agency (AEI) Unidad de Excelencia Maria de Maeztu-Centro de Astrobiologia (INTA-CSIC) [MDM-2017-0737], program Physique et Chimie du Milieu Interstellaire (INSU-CNRS), Centre National d'Etudes Spatiales (CNES) Centre National D'etudes Spatiales, PHC Procope (CAMPUS France) [42516WC], DAADDeutscher Akademischer Austausch Dienst (DAAD) [57445281], RIKEN, European Project: 664931,H2020,H2020-MSCA-COFUND-2014,AstroFIt2(2015), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Rico Villas, F. [0000-0002-5351-3497], Centre National D'Etudes Spatiales (CNES), European Research Council (ERC), Agencia Estatal de Investigación (AEI), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CINECA, European Commission (EU), Spanish FEDER, PHC Procope (CAMPUS France), Deutscher Akademischer Austauschdienst (DAAD), and Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC
- Subjects
Methods: laboratory: molecular ,laboratory: molecular [Methods] ,ISM: clouds ,ISM: molecules ,Methods: observational ,Molecular data ,Techniques: spectroscopic ,FOS: Physical sciences ,Context (language use) ,Astrophysics ,ISM: molecule ,01 natural sciences ,Spectral line ,spectroscopic [Techniques] ,Ab initio quantum chemistry methods ,ISM: cloud ,Distortion ,0103 physical sciences ,[CHIM]Chemical Sciences ,observational [Methods] ,Spectroscopy ,010303 astronomy & astrophysics ,molecules [ISM] ,Settore CHIM/02 - Chimica Fisica ,Physics ,010304 chemical physics ,Spectrometer ,Molecular cloud ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Interstellar medium ,13. Climate action ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Atomic physics ,clouds [ISM] - 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., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)
- Published
- 2020
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