J/A+A/646/L1 HDCCN discovery in space and in laboratory (Cabezas+, 2021)
Space and laboratory observation of the deuterated cyanomethyl radical HDCCN.
Cabezas C., Endo Y., Roueff E., Marcelino N., Agundez M., Tercero B.,
Cernicharo J.
<Astron. Astrophys. 646, L1 (2021)>
=2021A&A...646L...1C 2021A&A...646L...1C (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Interstellar medium ; Atomic physics
Keywords: astrochemistry - ISM: molecules - ISM: individual objects: TMC-1 -
line: identification - molecular data
Abstract:
Observations of TMC-1 with the Yebes 40m radio telescope in the
31.0-50.3GHz range allowed the detection of a group of unidentified
lines, showing a complex line pattern indicative of an open-shell
species. The observed frequencies of these lines and the similarity of
the spectral pattern with that of the 202-101 rotational
transition of H2CCN point to that the lines arise from the
deuterated cyanomethyl radical, HDCCN. Using Fourier transform
microwave spectroscopy experiments combined with electric discharges
we have succeeded in producing the radical HDCCN in the laboratory and
observed its 101-000 and 202-101 rotational transitions. From
our observations and assuming a rotational temperature of 5K, we
derive an abundance ratio H2CCN/HDCCN=20. The high abundance of the
deuterated form of H2CCN is well accounted for by a standard
gas-phase model where deuteration is driven by deuteron transfer from
the H2D+ molecular ion.
Description:
The table contains rotational transitions for HDCCN up to 300GHz.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
04 41 45.9 +25 41 27 TMC-1 = HCL 2
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table.dat 77 27032 Predicted frequencies for HDCCN
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.4 MHz Freq Frequency
12- 19 F8.4 MHz Unc Uncertainty on frequency
22- 28 F7.4 nm2.MHz Int Intensity
30- 37 F8.4 cm-1 Elow Lower state energy
40- 41 I2 --- N' Quantum number N for upper level
44- 45 I2 --- Ka' Quantum number Ka for upper level
48- 49 I2 --- Kc' Quantum number Kc for upper level
52- 53 I2 --- TSP' TSP aggregate spin number for upper level
56- 57 I2 --- F' Quantum number F for lower level
60- 61 I2 --- N" Quantum number N for lower level
64- 65 I2 --- Ka" Quantum number Ka for lower level
68- 69 I2 --- Kc" Quantum number Kc for lower level
72- 73 I2 --- TSP" TSP aggregate spin number for lower level
76- 77 I2 --- F" Quantum number F for lower level
--------------------------------------------------------------------------------
Acknowledgements:
Carlos Cabezas, carlos.cabezas(at)csic.es
(End) Patricia Vannier [CDS] 12-Jan-2021