J/A+A/661/A129 Transitions of cysteamine analysis (Song+, 2022)
Micro- and millimeter-wave spectra of five conformers of cysteamine
and their interstellar search.
Song W., Maris A., Rivilla V.M., Fortuna F., Evangelisti L., Lv D.,
Rodriguez-Almeida L., Jimenez-Serra I., Martin-Pintado J., Melandri S.
<Astron. Astrophys. 661, A129 (2022)>
=2022A&A...661A.129S 2022A&A...661A.129S (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Spectroscopy ; Molecular clouds
Keywords: ISM: molecules - techniques: spectroscopic -
methods: laboratory: molecular - molecular data - surveys -
line: identification
Abstract:
Cysteamine (NH2CH2CH2SH), a molecule of potential
astrobiological interest, has not yet been detected in the
interstellar medium. Furthermore, the sulfur-substituted isomer of
ethanolamine (or 2-aminoethanol) has been recently detected in the
molecular cloud G+0.693-0.027. In order to conduct a new interstellar
search for cysteamine in the molecular cloud G+0.693-0.027, its pure
rotational spectrum needs to be investigated in the laboratory. The
pulsed-jet Fourier transform microwave spectrometer and the
Stark-modulated free-jet millimeter-wave absorption spectrometer were
used to measure the purely rotational spectrum of cysteamine in the
range of 6.5-18GHz (46.12-16.66mm) and 59.6-120.0GHz (5.03-2.72mm),
respectively.
We used a deep spectral line survey toward the molecular cloud
G+0.693-0.027 obtained with the IRAM 30m and Yebes 40m
radiotelescopes to search for cysteamine.
We assigned 815 rotational transition lines of five conformers (gGt,
gGg, g'Gg, g'Gg', and g'Gt) to fit the rotational constants,
quartic centrifugal distortion constants, and the 14N nuclear
quadrupole coupling constants. For four conformers (gGt, gGg, g'Gg,
and g'Gg'), the 34S isotopologs were observed, and for two of them
(gGg and g'Gg), the 13C and 15N isotopolog spectra were also
detected; all are in natural abundance. The five conformers of
cysteamine were not detected toward the G+0.693-0.027 molecular cloud.
We derived upper limits for their molecular abundances compared to
molecular hydrogen of<(0.2-1.3)x10-10. The relative abundances
with respect to the oxygen counterpart ethanolamine, previously
detected toward this cloud, are
NH2CH2CH2OH/NH2CH2CH2SH>0.8-5.3.
Description:
The rotational spectra of cysteamine were recorded in the 6.5-18 GHz
and 59.6-103.6GHz frequency using pulsed-jet Fourier transform
microwave spectrometer and free-jet millimeter wave absorption
spectrometer, respectively. Five conformers were assigned: gGt, gGg,
g'Gg, g'Gg' and g'Gt.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables2.dat 56 163 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of the gGt conformer of cysteamine
tables3.dat 56 304 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of the gGg conformer of cysteamine
tables4.dat 56 191 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of the g'Gg conformer of cysteamine
tables5.dat 56 141 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of the g'Gg' conformer of cysteamine
tables6.dat 56 16 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of the g'Gt conformer of cysteamine
tables7.dat 56 16 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 34S mono substituted isotopologue
for conformer gGt of cysteamine
tables8.dat 56 25 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 34S mono substituted isotopologue
for conformer gGg of cysteamine
tables9.dat 56 12 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 13C-1 mono substituted
isotopologue for conformer gGg of cysteamine
tables10.dat 56 14 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 13C-2 mono substituted
isotopologue for conformer gGg of cysteamine
tables11.dat 56 4 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 15N mono substituted
isotopologue for conformer gGg of cysteamine
tables12.dat 56 20 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 34S mono substituted isotopologue
for conformer g'Gg of cysteamine
tables13.dat 56 12 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 13C-1 mono substituted
isotopologue for conformer g'Gg of cysteamine
tables14.dat 56 10 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 13C-2 mono substituted
isotopologue for conformer g'Gg of cysteamine
tables15.dat 56 4 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 15N mono substituted
isotopologue for conformer g'Gg of cysteamine
tables16.dat 56 12 Assignments, measured line positions and
least-squares residuals for the analysed
transitions of 34S mono substituted isotopologue
for conformer g'Gg' of cysteamine
tablec1.dat 75 1280 Predicted frequencies of the gGt conformer
of cysteamine
tablec2.dat 75 882 Predicted frequencies of the gGg conformer
of cysteamine
tablec3.dat 75 384 Predicted frequencies of the g'Gg conformer
of cysteamine
tablec4.dat 75 3217 Predicted frequencies of the g'Gg' conformer
of cysteamine
tablec5.dat 75 3439 Predicted frequencies of the g'Gt conformer
of cysteamine
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Byte-by-byte Description of file: tables[23456789].dat tables1[02346].dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- J' Upper state rotational quantum number J (1)
4- 5 I2 --- Ka' Upper state rotational quantum number Ka (1)
7- 8 I2 --- Kc' Upper state rotational quantum number Kc (1)
10- 11 I2 --- F' Upper state rotational quantum number F (1)
13- 15 I3 --- J Lower state rotational quantum number J (1)
17- 18 I2 --- Ka Lower state rotational quantum number Ka (1)
20- 21 I2 --- Kc Lower state rotational quantum number Kc (1)
23- 24 I2 --- F Lower state rotational quantum number F (1)
30- 40 F11.4 MHz FreqObs Experimental rest frequency (1)
43- 49 F7.4 MHz O-C Observed value minus calculated value (1)
52- 56 F5.3 MHz Error Experimental accuracy (1)
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Note (1): Transitions in 20-40GHz range are from Nandi's work.
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Byte-by-byte Description of file: tables11.dat tables15.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- J' Upper state rotational quantum number J
4- 5 I2 --- Ka' Upper state rotational quantum number Ka
7- 8 I2 --- Kc' Upper state rotational quantum number Kc
10- 12 I3 --- J Lower state rotational quantum number J
14- 15 I2 --- Ka Lower state rotational quantum number Ka
17- 18 I2 --- Kc Lower state rotational quantum number Kc
30- 40 F11.4 MHz FreqObs Experimental rest frequency
43- 49 F7.4 MHz O-C Observed value minus calculated value
52- 56 F5.3 MHz Error Experimental accuracy
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Byte-by-byte Description of file: tablec[12345].dat
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Bytes Format Units Label Explanations
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3- 13 F11.4 MHz Freq Predicted frequency from experimental
spectroscopic constants
16- 21 F6.4 MHz e_Freq Error of the prediction at 1-sigma level
23- 29 F7.4 [nm2.MHz] logI Base 10 logarithm of the integrated intensity
31 I1 --- DR Degrees of freedom in the rotational partition
function (0 for atoms, 2 for linear molecules,
and 3 for nonlinear molecules)
35- 41 F7.4 cm-1 ELO Lower state energy
43- 44 I2 --- Gup Upper state degeneracy Gup
49- 51 I3 --- TAG Species tag or molecular identifier
53- 55 I3 --- QNFMT Identifies the format of the quantum numbers
given in the field QN
56- 57 I2 --- J' Upper state rotational quantum number J
58- 59 I2 --- Ka' Upper state rotational quantum number Ka
60- 61 I2 --- Kc' Upper state rotational quantum number Kc
62- 63 I2 --- F' Upper state rotational quantum number F
68- 69 I2 --- J Lower state rotational quantum number J
70- 71 I2 --- Ka Lower state rotational quantum number Ka
72- 73 I2 --- Kc Lower state rotational quantum number Kc
74- 75 I2 --- F Lower state rotational quantum number F
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Acknowledgements:
Sonia Melandri,
References:
Nandi et al., J. Mol. Spectrosc., 92, 419
(End) W. Song [BO], S. Melandri [UniBo], P. Vannier [CDS] 20-Apr-2022