J/A+A/544/A82 Rotational spectroscopy of diisocyanomethane (Motiyenko+, 2012)
The submillimeter-wave spectrum of diisocyanomethane.
Motiyenko R.A., Margules L., Guillemin J.-C.
<Astron. Astrophys. 544, A82 (2012)>
=2012A&A...544A..82M 2012A&A...544A..82M
ADC_Keywords: Atomic physics
Keywords: ISM: molecules - methods: laboratory - submillimeter: ISM -
molecular data - line: identification
Abstract:
Several organic isocyanides have been observed so far in ISM (HNC,
CH3NC, HCCNC). However there is still a lack of high-resolution
spectroscopic data on simple iso- cyanides that could provide a basis
for their detection.
Diisocyanomethane (NC-CH2-CN) is a small molecule having only 7
atoms and being an interesting candidate for astrophysical detection.
Rotational spectrum of diisocyanomethane has never been studied
before.
We measured the rotational spectrum of diisocyanomethane in the
frequency range 120-620GHz using Lille fast-scan and solid-state
source spectrometers. The spectroscopic study was supported by
high-level theoretical calculations on molecular structure and both
harmonic and anharmonic force field.
The ground and the first excited vibrational state (v15) were assigned
and analyzed. The dataset is composed of more than 2000 measured and
fitted lines allows accurate predictions of transition frequencies of
diisocyanomethane in the range up to 900GHz. The statistical analysis
of the results of the fit shows that the use of S-reduction of Watson
rovibrational Hamiltonian for spectral modelling is more appropriate.
Description:
More than 2000 lines of the ground and first excited vibrational state
of diisocyanomethane were measured in the frequency range 120-620GHz.
They are listed in the tables. The molecule is an asymmetric top and
the fits were performed using Watson's A- and S-reduction Hamiltonians
in Ir representation. The tables contain line assignments, observed
frequencies, residuals of the fits using A and S-reductions and
accuracy of frequency measurement.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 74 1901 Assigned rotational transitions of the ground
state of diisocyanomethane
table3.dat 74 1141 Assigned rotational transitions of the first
excited vibrational state of diisocyanomethane
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Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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2- 3 I2 --- J" Upper J quantum number
5- 6 I2 --- Ka" Upper Ka quantum number
8- 9 I2 --- Kc" Upper Kc quantum number
13- 14 I2 --- J' Lower J quantum number
16- 17 I2 --- Ka' Lower Ka quantum number
19- 20 I2 --- Kc' Lower Kc quantum number
24- 36 F13.4 MHz Freq [130150/616700] Observed transition frequency
38 A1 --- bl [B] B if lines are blended
42- 48 F7.4 MHz O-CA Observed-Calculated frequencies for A-reduction
51- 57 F7.4 MHz O-CS Observed-Calculated frequencies for S-reduction
60- 66 F7.4 MHz unc Uncertainty of measurements (1)
68- 74 E7.2 --- Irel ? Relative intensity for blended line components
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Note (1): For the lines excluded from fit using S-reductions, uncertainties
of measurements have negative values.
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Acknowledgements:
Roman Motiyenko, motienko(at)univ-lille1.fr
(End) Roman Motiyenko [PhLAM, Lille 1], Patricia Vannier [CDS] 06-Jul-2012