J/A+A/652/A163 Rotational spectroscopy of dicyanobenzenes (Chitarra+, 2021)
Hunting the relatives of benzonitrile:
Rotational spectroscopy of dicyanobenzenes
Chitarra O., Lee K.L.K., Buchanan Z., Melosso M., McGuire B.A., Goubet M.,
Pirali O., Martin-Drumel M.-A.
<Astron. Astrophys. 652, A163 (2021)>
=2021A&A...652A.163C 2021A&A...652A.163C (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Spectroscopy
Keywords: methods: laboratory: molecular - techniques: spectroscopic -
astrochemistry - ISM: abundances - submillimeter: general
Abstract:
The recent interstellar detections of -CN containing aromatic
species, namely benzonitrile, 1-cyanonaphthalene, and
2-cyanonaphthalene, bring renewed interest in related molecules that
could participate in similar reaction networks.
To enable new interstellar searches for benzonitrile derivatives, the
pure rotational spectra of several related species need to be
investigated in the laboratory.
We have recorded the pure rotational spectra of ortho- and
meta-dicyanobenzene in the centimetre and millimetre-wave domains.
Assignments were supported by high-level quantum chemical
calculations. Using Markov chain Monte Carlo simulations, we also
searched for evidence of these molecules towards TMC-1 using the
GOTHAM survey.
Accurate spectroscopic parameters are derived from the analysis of the
experimental spectra, allowing for reliable predictions at
temperatures of interest (i.e. 10-300K) for astronomical searches.
Our searches in TMC-1 for both ortho- and meta-isomers provide upper
limits for the abundances of the species.
Description:
The measured transition line list, fit files, and partition functions
for 1,2-dicyanobenzene (1,2-DCB) and 1,3-dicyanobenzene (1,3-DCB)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
12-DCB_hfs.lin 54 5767 Measured transitions of 1,2-DCB
12-DCB_hfs.par 80 25 Spectroscopic parameters of 1,2-DCB
12-DCB_hfs.int 55 3 Prediction parameters of 1,2-DCB
12-DCB_hfs.fit 135 5911 fit file of 1,2-DCB
12-DCB_hfs.qpart 22 1000 Partition functions of 1,2-DCB
13-DCB_hfs.lin 54 7560 Measured transitions of 1,3-DCB
13-DCB_hfs.par 80 24 Spectroscopic parameters of 1,3-DCB
13-DCB_hfs.int 50 3 Prediction parameters of 1,3-DCB
13-DCB_hfs.fit 135 7695 fit file of 1,3-DCB
13-DCB_hfs.qpart 22 1000 Partition functions of 1,3-DCB
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Description of files: *.par *.int *.fit
These files are in standard CALPGM SPFIT/SPCAT format.
See Ref. Pickett H.M. 1991, Journal of Molecular Spectroscopy, 148, 371.
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Byte-by-byte Description of file: 12-DCB_hfs.lin 13-DCB_hfs.lin
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Bytes Format Units Label Explanations
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1- 3 I3 -- J'' Quantum number J of the upper state
4- 6 I3 -- Ka'' Quantum number Ka of the upper state
7- 9 I3 -- Kc'' Quantum number Kc of the upper state
10- 12 I3 -- vdummy'' Dummy quantum number v of the upper state (1)
13- 15 I3 -- I'' Quantum number I of the upper state
16- 18 I3 -- F'' Quantum number F of the upper state
19- 21 I3 -- J' Quantum number J of the lower state
22- 24 I3 -- Ka' Quantum number Ka of the lower state
25- 27 I3 -- Kc' Quantum number Kc of the lower state
28- 30 I3 -- vdummy' Dummy Quantum number v of the lower state
31- 33 I3 -- I' Quantum number I of the upper state
34- 36 I3 -- F' Quantum number F of the lower state
38- 48 F11.4 MHz Freq Line frequency observed
51- 54 F4.3 MHz Unc Line frequency uncertainty
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Note (1): the dummy quantum number (act as a vibrational state) is used to
combine the fit resolved and unresolved hyperfine lines. It does not have
physical meaning.
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Byte-by-byte Description of file (#): 12-DCB_hfs.qpart 13-DCB_hfs.qpart
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Bytes Format Units Label Explanations
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1- 6 F6.1 K T Temperature
8- 22 F15.4 -- Q Partition function
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Acknowledgements:
Olivia Chitarra, olivia.chitarra(at)universite-paris-saclay.fr
Marie-Aline Martin-Drumel, marie-aline.martin(at)universite-paris-saclay.fr
(End) Patricia Vannier [CDS] 23-Jun-2021