J/A+A/600/A44 Spectral line list of hydantoin (Ozeki+, 2017)
Millimeter-wave spectroscopy of hydantoin, a possible precursor of glycine.
Ozeki H., Miyahara R., Ihara H., Todaka S., Kobayashi K., Ohishi M.
<Astron. Astrophys. 600, A44 (2017)>
=2017A&A...600A..44O 2017A&A...600A..44O (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics
Keywords: line identification - molecular data - ISM: molecules -
submillimeter ISM
Abstract:
Hydantoin (Imidazolidine-2, 4-dione, C3H4N2O2) is a five-membered
heterocyclic compound that is known to arise from prebiotic molecules
such as glycolic acid and urea, and to give the simplest amino acid,
glycine, by hydrolysis under acidic condition. The gas chromatography
combined with the mass spectrometry of carbonaceous chondrites lead to
the detection of this molecule as well as several kinds of amino
acids.
The lack of spectroscopic information, especially on the rotational
constants, has prevented us from conducting a search for hydantoin in
interstellar space. If a rotational temperature of 100K is assumed as
the kinetic temperature of a star-forming region, the spectral
intensity is expected to be at its maximum in the millimeter-wave
region. Laboratory spectroscopy of hydantoin in the millimeter-wave
region is the most important in providing accurate rest frequencies to
be used for astronomical research.
Pure rotational spectra of hydantoin were observed in the
millimeter-wave region using the frequency modulated microwave
spectrometer at Toho University. Solid hydantoin was heated to around
150°C to provide appropriate vapor pressure. Quantum chemical
calculations suggest that the permanent dipole moment of this molecule
lies almost along the b-molecular axis, so that spectral search for
b-type R-branch transition has been conducted.
Description:
Spectral line list of hydantoin up to 500GHz is catalogued for the
ground and the first and the second vibrationally excited states.
Spectral intensity at T=100K is calculated with the permanent
dipole moment of 0.169 and 2.655-Debyes for along a- and b- molecular
axis, respectively, and for all vibrational levels.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
line.dat 63 53165 *Spectral line list of hydantoin
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Note on line.dat: This spectral line list is made by using SPFIT/SPCAT suite of
programs (Pickett, H. M., 1991, J. Mol. Spectrosc. 148, 371).
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Byte-by-byte Description of file: line.dat
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Bytes Format Units Label Explanations
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3- 13 F11.4 MHz Freq Frequency of the line
14- 21 F8.4 MHz e_Freq Estimated error
22- 29 F8.4 [nm2.MHz] logInt Base 10 logarithm of the integrated intensity
in units of nm2.MHz
30- 39 F10.4 cm-1 Elow Lower state energy in wavenumbers
40- 42 I3 --- Gup Upper state degeneracy
44- 45 A2 --- N' Upper state rotational quantum number
46- 47 I2 --- Ka' Upper state rotational quantum number
48- 49 A2 --- Kc' Upper state rotational quantum number
50- 51 I2 --- V' Upper state vibrational quantum number
56- 57 A2 --- N" Lower state rotational quantum number
58- 59 I2 --- Ka" Lower state rotational quantum number
60- 61 A2 --- Kc" Lower state rotational quantum number
62- 63 I2 --- V" Lower state vibrational quantum number
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Acknowledgements:
Hiroyuki Ozeki, ozeki(at)env.sci.toho-u.ac.jp
(End) Hiroyuki Ozeki [Toho University], Patricia Vannier [CDS] 08-Mar-2017