J/A+A/623/A93 Isotopic H2NCN laboratory spectroscopic study (Coutens+, 2019)
Laboratory spectroscopic study of the 15N isotopomers of cyanamide, H2NCN, and
a search for them toward IRAS 16293-2422 B.
Coutens A., Zakharenko O., Lewen F., Joergensen J.K., Schlemmer S.,
Mueller H.S.P.
<Astron. Astrophys. 623, A93 (2019)>
=2019A&A...623A..93C 2019A&A...623A..93C (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Spectroscopy ; Atomic physics
Keywords: molecular data - methods: laboratory: molecular -
techniques: spectroscopic - radio lines: ISM - ISM: molecules -
astrochemistry
Abstract:
Cyanamide is one of the few interstellar molecules containing two
chemically different N atoms. It was detected recently toward the
solar-type protostar IRAS 16293-2422 B together with H2N13CN and
HDNCN in the course of the Atacama Large Millemeter/submillimeter
Array (ALMA) Protostellar Interferometric Line Survey (PILS). The
detection of the 15N isotopomers or the determination of upper limits
to their column densities was hampered by the lack of accurate
laboratory data at the frequencies of the survey.
We wanted to determine spectroscopic parameters of the 15N
isotopomers of cyanamide that are accurate enough for predictions well
into the submillimeter region and to search for them in the PILS data.
Description:
We investigated the laboratory rotational spectra of H215NCN and
H2NC15N in the selected region between 192 and 507GHz employing a
cyanamide sample in natural isotopic composition. Additionally, we
recorded transitions of H2N13CN.
We obtained new or improved spectroscopic parameters for the three
isotopic species. Neither of the 15N isotopomers of cyanamide were
detected unambiguously in the PILS data. Two relatively clean lines
can be tentatively assigned to H215NCN. If confirmed, their column
densities would imply a low 14N/15N ratio for cyanamide toward
this source.
The resulting line lists should be accurate enough for observations up
to about 1THz. More sensitive observations, potentially at different
frequencies, may eventually lead to the astronomical detection of
these isotopic species.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
h215ncn.dat 94 209 Transitions included in the fit of H215NCN
h2n13cn.dat 94 204 Transitions included in the fit of H2N13CN
h2nc15n.dat 94 191 Transitions included in the fit of H2NC15N
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Byte-by-byte Description of file: h215ncn.dat h2n13cn.dat h2nc15n.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- J' Upper state J quantum number
5- 7 I3 --- Ka' Upper state Ka quantum number
8- 10 I3 --- Kc' Upper state Kc quantum number
11- 13 I3 --- v' Upper state inversion state (0: 0+, 1: 0-)
14- 16 I3 --- J" Lower state J quantum number
17- 19 I3 --- Ka" Lower state Ka quantum number
20- 22 I3 --- Kc" Lower state Kc quantum number
23- 25 I3 --- v" Lower state inversion state (0: 0+, 1: 0-)
29- 40 F12.5 MHz FreqObs Observed transition frequency
44- 50 F7.5 MHz e_FreqObs Experimental uncertainty
53- 60 F8.5 MHz (O-C) Observed minus calculated frequency
(for group of lines if they are at the same
frequency)
64- 69 F6.4 --- wb ? Weight of the component in group of lines
73- 94 A22 --- Notes Source of data (1)
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Note (1): References as follows:
Koeln = is from this work
Brown et al. (1985) = Brown et al., 1985JMoSp.114..257B 1985JMoSp.114..257B
Krasnicki et al., 2011 = Krasnicki et al., 2011JMoSp.267..144K 2011JMoSp.267..144K
Tyler et al. (1972) = Tyler et al., 1972JMoSp..43..248T 1972JMoSp..43..248T
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Acknowledgements:
Holger Mueller, hspm(at)ph1.uni-koeln.de
References:
Tyler et al., Paper I 1972JMoSp..43..248T 1972JMoSp..43..248T
https://doi.org/10.1016/0022-2852(72)90021-5
Brown et al., Paper II 1985JMoSp.114..257B 1985JMoSp.114..257B
https://doi.org/10.1016/0022-2852(85)90223-1
Krasnicki et al., Paper III 2011JMoSp.267..144K 2011JMoSp.267..144K
https://doi.org/10.1016/j.jms.2011.03.005
Coutens et al., 2018A&A...612A.107C 2018A&A...612A.107C
First detection of cyanamide (NH2CN) towards solar-type protostars
Mueller et al., 2001A&A...370L..49M 2001A&A...370L..49M,
The Cologne Database for Molecular Spectroscopy, CDMS
Endres et al., 2016JMoSp.327...95E 2016JMoSp.327...95E
https://doi.org/10.1016/j.jms.2016.03.005
(End) Patricia Vannier [CDS] 05-Jan-2019