J/A+A/623/A162 Spectroscopy of CH2(CN)2 and CNCH2CN (Motiyenko+, 2019)
Rotational spectroscopy of malononitrile and its corresponding monoisocyanide
isomer, isocyanoacetonitrile.
Motiyenko R.A., Armieieva I.A., Margules L., Alekseev E.A., Guillemin J.-C.
<Astron. Astrophys. 623, A162 (2019)>
=2019A&A...623A.162M 2019A&A...623A.162M
ADC_Keywords: Atomic physics ; Interstellar medium ; Millimetric/submm sources
Keywords: ISM: molecules - methods: laboratory: molecular -
submillimeter: ISM - molecular data - line: identification
Abstract:
Nitriles constitute almost 20% of the molecules observed in the
interstellar medium, whereas only one dinitrile and one
isocyanonitrile compound have been detected up to now. The lack of
detections of such compounds may be partially explained by the lack of
accurate spectroscopic data on their rotational spectra.
Two small seven-atom dinitriles, malononitrile NCCH2CN and
isocyanoacetonitrile NCCH2NC, were chosen as target species for this
study. For malononitrile the goal of the study is to systematize all
the previous measurements, and to extend the measurements to the
sub-millimeter wavelength range. The spectrum of isocyanoacetonitrile
has not been studied before.
The rotational spectra of the two molecules was measured in the
frequency range 150-660GHz using the Lille fast-scan spectrometer.
The spectroscopic study was supported by high-level theoretical
calculations on the structure of these molecules and their harmonic
force field.
Accurate frequency predictions for malononitrile and
isocyanoacetonitrile were calculated on the basis of the analysis of
their rotational spectra. The influence of the spin statistics on the
intensities of the lines of malononitrile was taken into account. The
provided line lists and sets of molecular parameters meet the needs of
astrophysical searches for the two molecules.
Description:
tablea1.dat contains calculated spectral predictions of the ground
state of malononitrile at T=300K and in the frequency range up to
700GHz.
tablea2.dat contains calculated spectral predictions of the ground
state of isocyanoacetonitrile at T=300K and in the frequency range up
to 700GHz.
tablea3.dat contains calculated the spectrum of malononitrile
including the nuclear quadrupole hyperfine structure, and for low
values of J quantum number in the range 0<J<15.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 58 12052 Predicted rotational transitions of the v=0
state of malononitrile at T=300K
tablea2.dat 58 21829 Predicted rotational transitions of the v=0
state of isocyanoacetonitrile at T=300K
tablea3.dat 70 4238 Predicted rotational transitions of the v=0
state of malononitrile at T=300K including the
nuclear quadrupole hyperfine structure
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Byte-by-byte Description of file: tablea1.dat tablea2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- J' Upper J quantum number
4- 6 I3 --- Ka' Upper Ka quantum number
7- 9 I3 --- Kc' Upper Kc quantum number
10- 12 I3 --- J" Lower J quantum number
13- 15 I3 --- Ka" Lower Ka quantum number
16- 18 I3 --- Kc" Lower Kc quantum number
19- 31 F13.4 MHz Freq Calculated transition frequency
32- 39 F8.4 MHz O-C Uncertainty of pcalculated transition frequency
40- 48 F9.4 [nm+2.MHz] logInt Base 10 logarithm of the integrated intensity
49- 58 F10.4 cm-1 Elo The energy of the lower state
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- J' Upper J quantum number
4- 6 I3 --- Ka' Upper Ka quantum number
7- 9 I3 --- Kc' Upper Kc quantum number
10- 12 I3 --- I' Upper I quantum number
13- 15 I3 --- F' Upper F quantum number
16- 18 I3 --- J" Lower J quantum number
19- 21 I3 --- Ka" Lower Ka quantum number
22- 24 I3 --- Kc" Lower Kc quantum number
25- 27 I3 --- I" Lower I quantum number
28- 30 I3 --- F" Lower F quantum number
31- 43 F13.4 MHz Freq Calculated transition frequency
44- 51 F8.4 MHz O-C Uncertainty of calculated transition frequency
52- 60 F9.4 [nm+2.MHz] logInt Base 10 logarithm of the integrated intensity
61- 70 F10.4 cm-1 Elo The energy of the lower state
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Acknowledgements:
Roman Motiyenko, roman.motiyenko(at)univ-lille.fr
(End) Roman Motiyenko [PhLAM, U Lille], Patricia Vannier [CDS] 21-Jan-2019