J/A+A/504/635 Dimethyl ether laboratory spectra up to 2.1THz (Endres+, 2009)
Dimethyl ether: laboratory spectra up to 2.1 THz.
Endres C.P., Drouin B.J., Pearson J.C., Muller H.S.P., Lewen F.,
Schlemmer S., Giesen T.F.
<Astron. Astrophys. 504, 635 (2009)>
=2009A&A...504..635E 2009A&A...504..635E
ADC_Keywords: Atomic physics
Keywords: ISM: molecules - molecular data - methods: laboratory -
techniques: spectroscopic - radio lines: ISM - submillimeter
Abstract:
Dimethyl ether (CH3OCH3) is one of the largest organic molecules
detected in the interstellar medium. As an asymmetric top molecule
with two methyl groups which undergo large amplitude motions and a
dipole moment of mub=1.3D it conveys a dense spectrum throughout
the terahertz region and contributes to the spectral line confusion in
astronomical observations at these frequencies. Rotational spectra of
dimethyl ether in its ground vibrational states are presented in this
paper, which have been measured in the laboratory and analyzed
covering frequencies up to 2.1THz. The analysis is based on an
effective Hamiltonian for a symmetric two-top rotor and includes
experimental data published so far. Frequency predictions are
presented up to 2.5THz for astronomical applications with accuracies
better than 1MHz.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 57 6830 Assigned and fitted transition frequencies of
dimethyl ether in the ground vibrational state
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See also:
J/ApJ/500/1059 : Dimethyl ether transitions frequencies (Groner+, 1998)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- t Torsional substates (1)
4- 5 I2 --- J' J' rotational quantum number
7- 8 I2 --- K'a K'a rotational quantum number
10- 11 I2 --- K'c K'c rotational quantum number
13- 14 I2 --- J" J" rotational quantum number
16- 17 I2 --- K"a K"a rotational quantum number
19- 20 I2 --- K"c K"c rotational quantum number
22- 32 F11.3 MHz Freq Frequency
34- 38 F5.3 MHz e_Freq rms uncertainty on Freq
40- 45 F6.3 MHz O-C Observed minus calculated frequency
47- 57 A11 --- Source Source (2)
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Note (1): Torsional substates are:
00 = AA
01 = EE
11 = AE
12 = EA
Note (2): Sources as follows:
Lovas = Lovas et al. 1979, J. Phys. Chem. Ref. Data 8, 1051
Durig = Durig et al. 1976, J. Molec. Spectrosc. 62, 159
Neustock = Neustock et al. 1990, Z. Naturforsch. 45a, 702
Niide = Niide et al. 2003, J. Molec. Spectrosc. 220, 65
Klystron = Groner et al. 1998, Cat. J/ApJ/500/1059
klystron-based measurements
FASSST = Groner et al. 1998, Cat. J/ApJ/500/1059
FASSST-based measurements
BWO = this work, BWO-based measurements done in Cologne
BWO_SL = this work, BWO + Superlattice multiplier based
measurements done in Cologne
Synthesizer = this work, Synthesizer-based measurements done in Cologne
JPL = this work, Multiplier chain-based measurements done at JPL
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Acknowledgements:
C.P. Endres, endres(at)ph1.uni-koeln.de
(End) Patricia Vannier [CDS] 03-Jul-2009