J/A+A/619/A140 g'G'Ag-CH3CH2CHOHCH2OH transition frequencies (Vigorito+, 2018)
Millimeter wave spectroscopy and modeling of 1,2-butanediol.
Laboratory spectrum in the 59.6-103.6 GHz region and comparison with the
ALMA archived observations.
Vigorito A., Calabrese C., Melandri S., Caracciolo A., Mariotti S.,
Giannetti A., Massardi M., Maris A.
<Astron. Astrophys. 619, A140 (2018)>
=2018A&A...619A.140V 2018A&A...619A.140V (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Spectra, millimetric/submm
Keywords: molecular data - line: identification -
methods: laboratory: molecular - methods: data analysis -
techniques: spectroscopic - radio lines: ISM
Abstract:
The continuously enhanced sensitivity of radioastronomical
observations allows the detection of increasingly complex organic
molecules. These systems often exist in a large number of isomers
leading to very congested spectra.
We explore the conformational space of 1,2-butanediol and provide sets
of spectroscopic parameters to facilitate searches for this molecule
at millimeter wavelengths.
We recorded the rotational spectrum of 1,2-butanediol in the
59.6-103.6GHz frequency region (5.03-2.89mm) using a free-jet
millimeter-wave absorption spectrometer, and we analyzed the
properties of 24 isomers with quantum chemical calculations. Selected
measured transition lines were then searched on publicly available
ALMA Band 3 data on IRAS 16293-2422 B.
We assigned the spectra of six conformers, namely aG'Ag, gG'Aa,
g'G'Ag, aG'G'g, aG'Gg, and g'GAa, to yield the rotational
constants and centrifugal distortion constants up to the fourth or
sixth order. The most intense signal belong to the aG'Ag species,
that is the global minimum. Search for the corresponding
30x,30-29x,29 transition lines toward IRAS 16293-2422 B was
unsuccessful.
Our present data will be helpful for identifying 1,2-butanediol at
millimeter wavelengths with radio telescope arrays. Among all possible
conformers, first searches should be focused on the aG'Ag conformers
in the 400-800GHz frequency spectral range.
Description:
The rotational spectrum of 1,2-butanediol was recorded in the
59.6-103.6GHz frequency using a free-jet millimeter wave absorption
spectrometer. Six conformers were assigned: aG'Ag, gG'Aa, g'G'Ag,
aG'G'g, aG'Gg, g'GAa.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 46 292 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
aG'Ag conformer of 1,2-butanediol
table2.dat 46 77 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
g'G'Ag conformer of 1,2-butanediol
table3.dat 46 65 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
gG'Aa conformer of 1,2-butanediol
table4.dat 46 66 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
gG'G'a conformer of 1,2-butanediol
table5.dat 46 57 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
aG'Gg conformer of 1,2-butanediol
table6.dat 46 68 Assignments, measured line positions and least-squares
residuals for the analysed transitions of the
g'GAa conformer of 1,2-butanediol
table7.dat 66 3996 *Predicted rest frequencies and Einstein's A coeff.
of the aG'Ag conformer of 1,2-butanediol.
table8.dat 66 3927 *Predicted rest frequencies and Einstein's A coeff.
of the g'G'Ag conformer of 1,2-butanediol
table9.dat 66 3503 *Predicted rest frequencies and Einstein's A coeff.
of the gG'Aa conformer of 1,2-butanediol
table10.dat 66 4718 *Predicted rest frequencies and Einstein's A coeff.
of the gG'G'a conformer of 1,2-butanediol
table11.dat 66 3921 *Predicted rest frequencies and Einstein's A coeff.
of the aG'Gg conformer of 1,2-butanediol
table12.dat 66 4256 *Predicted rest frequencies and Einstein's A coeff.
of the g'GAa conformer of 1,2-butanediol
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Note on table7.dat table8.dat table9.dat table10.dat table11.dat table12.dat:
Eupper<100K, A>10-7s-1 .
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Byte-by-byte Description of file: table[123456].dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- J' Upper state rotational quantum number J
5- 8 I4 --- Ka' ?=- Upper state rotational quantum number Ka (1)
9- 12 I4 --- Kc' ?=- Upper state rotational quantum number Kc (1)
13- 16 I4 --- J Lower state rotational quantum number J
17- 20 I4 --- Ka ?=- Lower state rotational quantum number Ka (1)
21- 24 I4 --- Kc ?=- Lower state rotational quantum number Kc (1)
25- 35 F11.2 MHz FreqObs Experimental rest frequency
36- 46 F11.2 MHz O-C Observed value minus calculated value
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Note (1): An '-' indicates an unresolved hyperfine structure.
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Byte-by-byte Description of file: table[789].dat table1[012].dat
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Bytes Format Units Label Explanations
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3- 4 I2 --- J' Upper state rotational quantum number J
7- 8 I2 --- Ka' Upper state rotational quantum number Ka
11- 12 I2 --- Kc' Upper state rotational quantum number Kc
15- 16 I2 --- J Lower state rotational quantum number J
19- 20 I2 --- Ka Lower state rotational quantum number Ka
23- 24 I2 --- Kc Lower state rotational quantum number Kc
27- 36 F10.3 MHz Freq Rest frequency from spectroscopic constants
39- 43 F5.3 MHz e_Freq Error of the prediction at 1-sigma level
46- 47 I2 --- Gup Upper state degeneracy Gup
50- 55 F6.3 K Eup Upper state energy Eup
58- 66 E9.3 s-1 A Einstein's A coefficient
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Acknowledgements:
Assimo Maris, assimo.maris(at)unibo.it
(End) Assimo Maris [UniBo, Italy], Patricia Vannier [CDS] 31-Jul-2018