J/A+A/563/A137 THz spectrum of methylamine (Motiyenko+, 2014)
Rotational spectroscopy of methylamine up to 2.6 THz.
Motiyenko R.A., Ilyushin, V.V., Drouin B.J., Yu.S., Margules L.
<Astron. Astrophys. 563, A137 (2014)>
=2014A&A...563A.137M 2014A&A...563A.137M
ADC_Keywords: Atomic physics ; Interstellar medium ; Millimetric/submm sources
Keywords: ISM: molecules - methods: laboratory: molecular -
submillimeter: ISM - molecular data - line: identification
Abstract:
Methylamine (CH3NH2) is the simplest primary alkylamine and has
been detected in the interstellar medium. The molecule is relatively
light, with the 50K Boltzmann peak appearing near 800GHz. However,
reliable predictions for its rotational spectrum are available only up
to 500GHz. Spectroscopic analyses have been complicated by the two
large amplitude motions: internal rotation of the methyl top and
inversion of the amino group.
The aims is to provide reliable predictions of the methylamine ground
state rotational spectrum above 500GHz we studied its rotational
spectrum in the frequency range from 500 to 2650GHz.
The spectra of methylamine were recorded using the spectrometers based
on Schottky diode frequency multiplication chains in the Lille
laboratory (500-945GHz) and in JPL (1060-2660GHz). The analysis
of the rotational spectrum of methylamine in the ground vibrational
state was performed on the basis of the group-theoretical high barrier
tunneling Hamiltonian developed for methylamine by Ohashi and Hougen.
In the recorded spectra we have assigned 1849 new rotational
transitions of methylamine. They were fitted together with previously
published data to a Hamiltonian model that uses 76 parameters with
overall weighted rms deviation of 0.87. On the basis of the new
spectroscopic results, predictions of transition frequencies in the
frequency range up to 3THz with J<50 and Ka<20 are presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 59 3343 Measured rotational transitions of methylamine
(CH3NH2) in the ground vibrational state
table3.dat 73 86056 Predicted transitions of methylamine in the
ground vibrational state
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See also:
J/A+A/493/565 : Deuterated and 15N ethyl cyanides (Margules+, 2009)
J/A+A/538/A51 : Rotational spectrum of CH3CH(NH2)CN (Mollendal+, 2012)
J/A+A/538/A119 : Spectrum of 18O-methyl formate (HCO18OCH3) (Tercero+ 2012)
J/A+A/540/A51 : Submm spectrum of deuterated glycolaldehydes (Bouchez+, 2012)
J/A+A/543/A46 : Submillimeter spectrum of HCOOCD2H (Coudert+, 2012)
J/A+A/543/A135 : New analysis of 13C-CH3CH2CN up to 1THz (Richard+, 2012)
J/A+A/544/A82 : Rotational spectroscopy of diisocyanomethane (Motiyenko+, 2012
J/A+A/548/A71 : Spectroscopy and ISM detection of formamide (Motiyenko+, 2012)
J/A+A/549/A96 : The mm & sub-mm spectra of 13C-glycolaldehydes (Haykal+, 2013)
J/A+A/549/A128 : Singly deuterated isotopologues of formamide (Kutsenko+, 2013)
J/A+A/552/A117 : Mono-deuterated dimethyl ether (Richard+, 2013)
J/A+A/553/A84 : (Sub)mm spectrum of deuterated methyl cyanides (Nguyen+, 2013)
J/A+A/559/A44 : Rotational spectrum of MAAN (CH2NCH2CH) (Motiyenko+, 2013)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- J1 [1/44] Upper J quantum number
4- 6 I3 --- Ka1 [0/19] Upper Ka quantum number
8- 11 A4 --- G1 Upper symmetry species Γ (G1)
12- 14 I3 --- J0 [0/44] Lower J quantum number
15- 17 I3 --- Ka0 [0/18] Lower Ka quantum number
19- 22 A4 --- G0 Lower symmetry species Γ (G1)
25- 37 F13.4 MHz Freq [5/2661539] Observed transition frequency
39- 46 F8.4 MHz Error [-0.001/0.5] Uncertainty of measurements
48- 55 F8.4 MHz O-C [-1/1] Residuals of the fit
58- 59 I2 --- Ref [1/11] Reference (1)
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Note (1): References as follows:
1 = this study
2 = Shimoda, Nishikawa & Itoh, 1954, J. Phys. Soc. Jpn., 9, 974
3 = Lide, 1954, J. Chem. Phys., 22, 1613
4 = Hirakawa, Miyahara & Shimoda, 1956, J. Phys. Soc. Jpn., 11, 334
5 = Nishikawa, T. 1957, J. Phys. Soc. Jpn., 12, 668
6 = Takagi, & Kojima, 1971, J. Phys. Soc. Jpn., 30, 1145
7 = Takagi, & Kojima, 1973, ApJ, 181, L91
8 = Ohashi & Hougen, 1987, J. Mol. Spec., 121, 474
9 = Kreglewski, Stahl, Grabow, & Wlodarczak, 1992 Chem. Phys. Lett., 196, 155
10 = Kreglewski & Wlodarczak, 1992, J. Mol. Spectrosc., 156, 383
11 = Ilyushin, Alekseev, Dyubko, Motiyenko, Hougen, 2005,
J. Mol. Spec., 229, 170
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- J1 [1/50] Upper J quantum number
4- 6 I3 --- Ka1 [0/20] Upper Ka quantum number
8- 11 A4 --- G1 Upper symmetry species Γ (G1)
12- 14 I3 --- F1 [0/51] Upper F quantum number
16- 18 I3 --- J0 [0/50] Lower J quantum number
19- 21 I3 --- Ka0 [0/20] Lower Ka quantum number
23- 26 A4 --- G0 Lower symmetry Γ0 specie (G1)
27- 29 I3 --- F0 [0/51] Lower F quantum number
31- 43 F13.4 MHz Freq [1019/2999600] Calculated transition frequency
45- 51 F7.4 MHz Error [0.0005/0.9995] Calculated uncertainty
54- 60 F7.3 D2 mu2S [0/49] Calculated line strength
62- 63 I2 --- Wst [1/3] Statistical weight
65- 73 F9.3 cm-1 E0 [0/2508] Energy of the lower state
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Global Notes:
Note (G1): symmetries are A1, A2, B1, B2, E1+1, E1-1, E2+1, E2-1
Acknowledgements:
Roman Motiyenko, roman.motienko(at)univ-lille1.fr
(End) Roman Motiyenko [PhLAM, Lille 1], Patricia Vannier [CDS] 28-Jan-2014