J/A+A/624/A70 Acetaldehyde CH2DCOH and CH3COD (Coudert+, 2019)
Astrophysical detections and databases for the mono deuterated species of
acetaldehyde CH2DCOH and CH3COD.
Coudert L., Margules L., Vastel C., Motiyenko R., Caux E., Guillemin J.-C.
<Astron. Astrophys. 624, A70 (2019)>
=2019A&A...624A..70C 2019A&A...624A..70C (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Radio lines
Keywords: molecular data - catalogs - radio lines: ISM
Abstract:
Detection of deuterated species may provide information on the
evolving chemistry in the earliest phases of star-forming regions. For
molecules with two isomeric forms of the same isotopic variant,
gas-phase and solid-state formation pathways can be differentiated
using their abundance ratio.
Spectroscopic databases for astrophysical purposes are built for the
two mono deuterated isomeric species CH2DCOH and CH3COD of the complex
organic molecule acetaldehyde. These databases can be used to search
and detect these two species in astrophysical surveys, retrieving
their column density and therefore abundances.
Submillimeter wave and terahertz transitions were measured for mono
deuterated acetaldehyde CH2DCOH which is a non-rigid species
displaying internal rotation of its asymmetrical CH2D methyl group.
An analysis of a dataset consisting of previously measured microwave
data and the newly measured transition was carried out with a model
accounting for the large amplitude torsion.
The frequencies of 2556 transitions are reproduced with a unitless
standard deviation of 2.3 yielding various spectroscopic constants.
Spectroscopic databases for astrophysical purposes were built for
CH2DCOH using the results of the present analysis and for CH3COD
using the results of a previous spectroscopic investigation. These two
species were both searched for and are detected toward a low-mass
star-forming region.
We report the first detection of CH2DCOH (93 transitions) and the
detection of CH3COD (43 transitions) species in source B of the
IRAS 16293-2422 young stellar binary system located in the
ρ Ophiuchus cloud region, using the publicly available ALMA
Protostellar Interferometric Line Survey.
Description:
Microwave, submillimeter wave, and terahertz transitions of CH2DCOH
analyzed in this work. Assignments, observed frequencies and
observed minus calculated residual are listed.
Spectroscopic parameters determined in the line frequency analysis.
Linelists with calculated line frequency and intensity for the two
isomeric species of monodeuterated acetaldehyde CH2DCOH and
CH3COD. Linelists are formatted as the JPL data base catalog line
files (Pickett, Poynter, Cohen et al. 1998, J. Quant. Spectrosc.
Radiat. Transfer, 60, 883).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 67 2556 Observed minus calculated table CH2DCOH
table4.dat 34 71 Spectroscopic constants for CH2DCOH
table7.dat 75 7410 Linelists for CH2DCOH
table8.dat 75 8763 Linelists for CH3COD
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See also:
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- J' Upper level rotational quantum number J
4- 6 I3 --- Ka' Upper level rotational quantum number Ka
7- 9 I3 --- Kc' Upper level rotational quantum number Kc
11 A1 --- v' [±0] Upper level vibrational quantum
number label (1)
14- 16 I3 --- J" Lower level rotational quantum number J
17- 19 I3 --- Ka" Lower level rotational quantum number Ka
20- 22 I3 --- Kc" Lower level rotational quantum number Kc
24 A1 --- v" [±0] Lower level vibrational quantum
number label (1)
26- 36 F11.3 MHz Freq Observed frequency
38- 40 I3 kHz Unc Experimental uncertainty
43- 47 I5 kHz O-C Observed minus calculated frequency
48 A1 --- double [ d] Doublet label (2)
50- 67 A18 --- Ref Reference from which the line was taken (3)
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Note (1): level vibrational quantum number label as follows:
+ = Out Conformation
- = Out Conformation
0 = In Conformation
Note (2): Doublet label code as follows:
d = Unresolved doublet line
blank = Singlet line
Note (3): References as follows:
This work = This work
Turner & Cox 1976 = Turner & Cox, 1976CPL....42...84T 1976CPL....42...84T
Turner et al. 1981 = Turner et al., 1981, J. Chem. Soc. Faraday Trans., 2, 1217
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Param Spectroscopic parameter label
12- 24 E13.7 cm-1 Value Parameter value (1)
27- 34 E8.2 cm-1 Unc Parameter uncertainty
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Note (1): Values and uncertainties for parameters theta_2, phi_2, theta_2j,
phi_2j, chi_3, theta_3, phi_3 are in degrees.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.4 MHz Freq Calculated or observed line frequency
14- 21 F8.4 MHz e_Freq Frequency Uncertainty
22- 29 F8.4 [nm+2.MHz] logInt Base 10 logarithm of the integrated
intensity in units of nm**2 MHz at 300 K
31 I1 --- DOF [3] Number of degrees of freedom.
32- 41 F10.4 cm-1 Elow Lower state energy in cm-1
42- 44 I3 --- Gup Upper state degeneracy
45- 51 I7 --- Species Species code (G1)
52- 55 I4 --- QNFMT [1404] JPL-type number describing the quantum
numbers format (14004)
56- 57 I2 --- J' Upper level rotational quantum number J
58- 59 I2 --- Ka' Upper level rotational quantum number Ka
60- 61 I2 --- Kc' Upper level rotational quantum number Kc
63 I1 --- v' [0/2] Upper level vibrational quantum
number (1)
68- 69 I2 --- J" Lower level rotational quantum number J
70- 71 I2 --- Ka" Lower level rotational quantum number Ka
72- 73 I2 --- Kc" Lower level rotational quantum number Kc
75 I1 --- v" [0/2] Lower level vibrational quantum
number (1)
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Note (1): vibrational quantum number as follows:
0 = In Conformation
1 = Out Conformation (+)
2 = Out Conformation (-)
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.4 MHz Freq Calculated or observed line frequency
14- 21 F8.4 MHz e_Freq Frequency Uncertainty
22- 29 F8.4 [nm+2.MHz] logInt Base 10 logarithm of the integrated
intensity in units of nm**2 MHz at 300 K
31 I1 --- DOF [3] Number of degrees of freedom.
32- 41 F10.4 cm-1 Elow Lower state energy in cm-1
42- 44 I3 --- Gup Upper state degeneracy
45- 51 I7 --- Species Species code (G1)
52- 55 I4 --- QNFMT [1404] JPL-type number describing the quantum
numbers format (14004)
56- 57 I2 --- J' Upper level rotational quantum number J
58- 59 I2 --- Ka' Upper level rotational quantum number Ka
60- 61 I2 --- Kc' Upper level rotational quantum number Kc
63 I1 --- v' [0/5] Upper level vibrational quantum
number (1)
68- 69 I2 --- J" Lower level rotational quantum number J
70- 71 I2 --- Ka" Lower level rotational quantum number Ka
72- 73 I2 --- Kc" Lower level rotational quantum number Kc
75 I1 --- v" [0/5] Lower level vibrational quantum
number (1)
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Note (1): vibrational quantum number as follows:
0 = A-type level vt=0
1 = E-type level vt=0
2 = E-type level vt=0
3 = E-type level vt=1
4 = E-type level vt=1
5 = A-type level vt=1
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Global notes:
Note (G1): Species code:
45001 for CH2DCOH (table7), 45000 for CH3COD (table8).
A minus sign in front of the tag indicates that the value given
for the frequency (Freq) is the observed one.
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Acknowledgements:
Laurent Coudert, laurent.coudert(at)u-psud.fr
(End) Laurent Coudert [CNRS, France], Patricia Vannier [CDS] 28-Feb-2019