J/A+A/579/A46 Mono-13C acetaldehydes mm/submm wave spectra (Margules+, 2015)
Millimeter and submillimeter wave spectra of mono-13C acetaldehydes.
Margules L., Motiyenko R.A., Ilyushin V.V., Guillemin J.-C.
<Astron. Astrophys. 579, A46 (2015)>
=2015A&A...579A..46M 2015A&A...579A..46M
ADC_Keywords: Atomic physics ; Spectra, millimetric/submm
Keywords: ISM: molecules - methods: laboratory: molecular - submillimeter: ISM -
molecular data - line: identification
Abstract:
The acetaldehyde molecule is ubiquitous in the interstellar medium of
our galaxy, and due to its dense and complex spectrum, large dipole
moment, and several low-lying torsional states, acetaldehyde is
considered to be a "weed" molecule for radio astronomy
observations. Mono-13C acetaldehydes 13CH3CHO and CH313CHO
are likely to be identified in astronomical surveys, such as those
available with the very sensitive ALMA telescope. Laboratory
measurements and analysis of the millimeter and submillimeter-wave
spectra are the prerequisites for the successful radioastronomical
search for the new interstellar molecular species, as well as for new
isotopologs of already detected interstellar molecules.
In this context, to provide reliable predictions of 13CH3CHO and
CH313CHO spectra in millimeter and submillimeter wave ranges, we
study rotational spectra of these species in the frequency range from
50 to 945GHz.
The spectra of mono-13C acetaldehydes were recorded using the
spectrometer based on Schottky-diode frequency-multiplication chains
in the Lille laboratory. The rotational spectra of 13CH3CHO and
CH313CHO molecules were analyzed using the Rho axis method.
Description:
This paper is a continuation of a series of studies conducted in PhLAM
Lille (France) that are devoted to the investigations of the spectra
of different isotopic species of astrophysical molecules.
We present a new study of the 13CH3CHO and CH313CHO spectra
with measurements and analysis extended up to 945GHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 80 7693 Assignments, measured transition frequencies, and
residuals from the global fit of the microwave,
millimeter-wave and submillimeter-wave vt=0,1,2
data for 13C acetaldehyde 13CH3CHO
table4.dat 80 7275 Assignments, measured transition frequencies, and
residuals from the global fit of the microwave,
millimeter-wave and submillimeter-wave vt=0,1,2
data for 13C acetaldehyde CH313CHO
table5a.dat 33 30 Torsion-rotation part Qrt(T) of the total internal
partition function Q(T)=Qv(T)*Qrt(T), calculated
from first principles using the parameter set of
Table 1 for 13C acetaldehyde 13CH3CHO.
table5.dat 77 28789 A list of calculated positions and assignments of
A-A and E-E transitions in the vt=0,1 torsional
states of 13C acetaldehyde 13CH3CHO up to
J=65 in the 1-1000GHz frequency range.
table6a.dat 33 30 Torsion-rotation part Qrt(T) of the total internal
partition function Q(T)=Qv(T)*Qrt(T), calculated
from first principles using the parameter set of
Table 1 for 13C acetaldehyde CH313CHO
table6.dat 77 28026 A list of calculated positions and assignments of
A-A and E-E transitions in the vt=0,1 torsional
states of 13C acetaldehyde CH313CHO up to
J=65 in the 1-1000GHz frequency range
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Byte-by-byte Description of file: table3.dat table4.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Sy1 Upper level symmetry in the G6 group: E, A1 or A2
5 I1 --- vt1 [0/2] Upper level torsional quantum number
8- 9 I2 --- J1 [1/60] Upper level asymmetric top rotational
quantum number
12- 13 I2 --- Ka1 [0/22] Upper level asymmetric top rotational
quantum number
16- 17 I2 --- Kc1 [0/55] Upper level asymmetric top rotational
quantum number
22- 23 A2 --- Sy0 Lower level symmetry in the G6 group: E, A1 or A2
26 I1 --- vt0 [0/2] Lower level torsional quantum number
29- 30 I2 --- J0 [0/60] Lower level asymmetric top rotational
quantum number
33- 34 I2 --- Ka0 [0/22] Lower level asymmetric top rotational
quantum number
37- 38 I2 --- Kc0 [0/56] Lower level asymmetric top rotational
quantum number
40- 50 F11.4 MHz Pos [9513/944843] Measured line position
52- 57 F6.4 MHz e_Pos [0.03/4] Uncertainty of Pos
59- 65 F7.4 MHz O-C [-1.1/9.4] Residuals from the global fit
67- 70 A4 --- Ref Source of data (1)
72 A1 --- Blend [b] b for blended lines
74- 80 F7.4 MHz Delta [-0.4/0.3]? Differences between the
intensity-weighted average of calculated (but
experimentally unresolved) transition wavenumbers
(or frequencies in case of microwave data) and
the observed position of the cluster of blended
lines
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Note (1): References (unlabeled data are from the present work):
KLW = R.W. Kilb, C.C. Lin, E.B. Wilson, 1957, The Journal of Chemical
Physics Vol. 26, #6, pp. 1695-1703
KLW* = one measured line from Kilb et al. 1957 labeled by '*'
was excluded from the fit.
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Byte-by-byte Description of file: table5a.dat table6a.dat
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Bytes Format Units Label Explanations
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1- 3 I3 K T [10/300] Temperature (1)
5- 13 F9.3 --- Qrt(A+E) A+E parts of the torsion-rotation part of
partition function
15- 23 F9.4 --- Qrt(A) ? A part of the torsion-rotation part of
partition function
25- 33 F9.4 --- Qrt(E) ? E part of the torsion-rotation part of
partition function
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Note (1): For the temperatures below 100K the separate A and E parts of the
torsion-rotation part of partition function are given, where the A and E
type levels are treated as the independent subsets of energy levels.
The vibrational part Qv(T) (omitting the torsional vibration since it is
taken into account in Qrt) may be estimated in the harmonic approximation
using the vibrational frequencies reported for the parent species of
acetaldehyde by T. Schimanouchi, Tables of Molecular Vibrational Frequencies,
Vol. I: consolidated (National Bureau of Standards, Washington, DC, 1972),
pp. 1-160. In the calculation the states up to J=100 and vt=8 were included.
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Byte-by-byte Description of file: table5.dat table6.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Sy1 Upper level symmetry in the G6 group: E, A1 or A2
5 I1 --- vt1 [0/1] Upper level torsional quantum number
8- 9 I2 --- J1 [1/65] Upper level asymmetric top rotational
quantum number
12- 13 I2 --- Ka1 [0/25] Upper level asymmetric top rotational
quantum number
16- 17 I2 --- Kc1 [0/61] Upper level asymmetric top rotational
quantum number
22- 23 A2 --- Sy0 Lower level symmetry in the G6 group: E, A1 or A2
26 I1 --- vt0 [0/1] Lower level torsional quantum number
29- 30 I2 --- J0 [0/65] Lower level asymmetric top rotational
quantum number
33- 34 I2 --- Ka0 [0/25] Lower level asymmetric top rotational
quantum number
37- 38 I2 --- Kc0 [0/62] Lower level asymmetric top rotational
quantum number
40- 50 F11.4 MHz Pos [1001/999998] Measured line position (1)
52- 57 F6.4 MHz e_Pos [0.0001/0.1] Uncertainty of Pos
59- 67 F9.4 cm-1 E0 [0/1633] Lower state energy
69- 77 E9.4 D2 mu2S Dipole moment squared multiplied by the
transition linestrength µ2S
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Note (1): Note that only transitions with predicted uncertainties below
0.1MHz cutoff are given in the list.
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Acknowledgements:
Laurent Margules, laurent.margules(at)univ-lille1.fr
(End) Patricia Vannier [CDS] 30-Jun-2015