Millimeter‐Wave Rotational Spectrum of HSSH and DSSD. I. Q Branches

1968 ◽  
Vol 49 (8) ◽  
pp. 3465-3478 ◽  
Author(s):  
Gisbert Winnewisser ◽  
Manfred Winnewisser ◽  
Walter Gordy
Keyword(s):  
Millimeter Wave ◽  
Rotational Spectrum

scholarly journals Millimeter-wave spectroscopy and modeling of 1,2-butanediol

2018 ◽  
Vol 619 ◽  
pp. A140 ◽  
Author(s):  
A. Vigorito ◽  
C. Calabrese ◽  
S. Melandri ◽  
A. Caracciolo ◽  
S. Mariotti ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Conformational Space ◽  
Rotational Spectrum ◽  
Free Jet ◽  
Enhanced Sensitivity ◽  
Millimeter Wavelengths ◽  
Global Minimum Search ◽  
Centrifugal Distortion Constants ◽  
Telescope Arrays ◽  
Complex Organic

Context. 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. Aims. We explore the conformational space of 1,2-butanediol and provide sets of spectroscopic parameters to facilitate searches for this molecule at millimeter wavelengths. Methods. We recorded the rotational spectrum of 1,2-butanediol in the 59.6–103.6 GHz frequency region (5.03–2.89 mm) 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. Results. 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. Conclusions. 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 400–800 GHz frequency spectral range.

scholarly journals Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

2018 ◽  
Vol 616 ◽  
pp. A173 ◽  
Author(s):  
L. Kolesniková ◽  
E. R. Alonso ◽  
B. Tercero ◽  
J. Cernicharo ◽  
J. L. Alonso
Keyword(s):  
Millimeter Wave ◽  
High Mass ◽  
Mass Star ◽  
Rotational Spectrum ◽  
Torsional Mode ◽  
Star Forming ◽  
Star Forming Regions ◽  
Ethyl Isocyanate ◽  
Wave Region ◽  
Centrifugal Distortion Constants

Context. Relatively high abundances of methyl isocyanate (CH3NCO), a methyl derivative of isocyanic acid (HNCO), found in the Orion KL and Sgr B2 molecular clouds suggest that its ethyl derivative, ethyl isocyanate (CH3CH2NCO), may also be present. Aims. The aim of this work is to provide accurate experimental frequencies of ethyl isocyanate in its ground and excited vibrational states in the millimeter wave region to support searches for it in the interstellar medium. Methods. The rotational spectrum of ethyl isocyanate was recorded at room temperature from 80 to 340 GHz using the millimeter wave spectrometer in Valladolid. Assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. Results. More than 1100 distinct frequency lines were analyzed for the ground vibrational state of the cis conformer as well as for three vibrational satellites corresponding to successive excitation of the lowest-frequency C–N torsional mode. Newly determined rotational and centrifugal distortion constants were used for searches of spectral features of ethyl isocyanate in Orion KL and Sgr B2 clouds. Upper limits to CH3CH2NCO in these high-mass star-forming regions were obtained.

Millimeter wave rotational spectrum of gallium monofluoride

1993 ◽  
Vol 215 (4) ◽  
pp. 371-374 ◽  
Author(s):  
J. Hoeft ◽  
K.P.R. Nair
Keyword(s):  
Millimeter Wave ◽  
Rotational Spectrum

scholarly journals The pure rotational spectrum of the T-shaped AlC2 radical (X̃2A1)

2018 ◽  
Vol 20 (16) ◽  
pp. 11047-11052 ◽  
Author(s):  
D. T. Halfen ◽  
L. M. Ziurys
Keyword(s):  
Fourier Transform ◽  
Millimeter Wave ◽  
Rotational Spectrum ◽  
Frequency Range

The pure rotational spectrum of the AlC2 radical (X̃2A1) has been measured using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the frequency range 21–65 GHz.

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