J/A+A/657/A24 HCCCHCN laboratory observations (Cabezas+, 2022)
Laboratory observation and astronomical search of 1-cyano propargyl radical,
HCCCHCN.
Cabezas C., Nakajima M., Chang C.H., Agundez M., Endo Y., Cernicharo J.
<Astron. Astrophys. 657, A24 (2022)>
=2022A&A...657A..24C 2022A&A...657A..24C (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: astrochemistry - ISM: molecules - ISM: individual objects: TMC-1 -
methods: laboratory: molecular - molecular processes
Abstract:
The reaction between carbon atoms and vinyl cyanide, CH2CHCN, is a
possible formation route for interstellar 3-cyano propargyl radical,
CH2C3N. 1-Cyano propargyl radical (HC3HCN), an isomer of
CH2C3N, is predicted to be produced in the same reaction at least
twice more efficiently than CH2C3N. Hence, HC3HCN is a plausible
candidate to be observed in space as well. We aim to generate HC3HCN
radical in the gas phase in order to investigate its rotational
spectrum. The derived spectroscopic parameters for this species will
be use to obtain reliable frequency predictions to support its
detection in the space. Rotational spectrum of HC3HCN radical was
produce by electric discharges and characterized using a Balle-Flygare
narrowband type Fourier-transform microwave (FTMW) spectrometer
operating in the frequency region of 4-40GHz. The spectral analysis
was supported by high-level ab initio calculations. A total of 193
hyperfine components originated from twelve rotational transitions, a-
and b-type, were measured for HC3HCN radical. The analysis allowed
us to accurately determine twenty-two molecular constants, including
rotational and centrifugal distortion constants as well as the fine
and hyperfine constants. Transition frequency predictions were used to
search for HC3HCN radical in TMC-1 using the QUIJOTE survey between
30.1-50.4GHz. We can not confirm the presence of HC3HCN in TMC-1 and
obtain an upper limit to the column density of HC3HCN in TMC-1 of
6.0*1011cm-2.
Description:
We report the investigation of the rotational spectrum of 1-cyano
propargyl radical, HC3HCN. This transient species was generated in
the gas phase using an electric discharges technique and was then
characterized by Fourier transform microwave spectroscopy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 67 60708 Predicted frequencies for HC3HCN at 10K
tablea3.dat 67 43202 Predicted frequencies for HC3HCN at 300K
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Byte-by-byte Description of file: tablea2.dat tablea3.dat
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Bytes Format Units Label Explanations
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3- 13 F11.4 MHz Freq Calculated transition frequency
15- 21 F7.4 MHz O-C Uncertainty of calculated transition frequency
23- 30 F8.4 [nm+2.MHz] logInt Base 10 logarithm of the integrated intensity
33- 40 F8.4 cm-1 Elo The energy of the lower state
42- 43 I2 --- gu Degeneracy of the upper level
46- 47 I2 --- J' Quantum number J for upper level
48- 49 I2 --- Ka' Quantum number Ka for upper level
50- 51 I2 --- Kc' Quantum number Kc for upper level
52- 53 I2 --- TSP' Aggregate spin number for upper level
54- 55 I2 --- It' Quantum number Itotal for upper level
57- 59 I3 --- J" Quantum number J for lower level
60- 61 I2 --- Ka" Quantum number Ka for lower level
62- 63 I2 --- Kc" Quantum number Kc for lower level
64- 65 I2 --- TSP" Aggregate spin number for lower level
66- 67 I2 --- It" Quantum number Itotal for lower level
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Acknowledgements:
Carlos Cabezas, carlos.cabezas(at)csic.es
(End) Patricia Vannier [CDS] 19-Oct-2021