Far-infrared spectrum and ground state constants of methyl amine

Ohashi, Nobukimi; Takagi, Kojiro; Hougen, Jon T.; Olson, W. B.; Lafferty, W. J.

doi:10.1016/0022-2852(87)90249-9

Cited by 73 publications

(63 citation statements)

References 19 publications

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“…(9,10), and fitted to the same symmetry adapted analytical form in Eq. [5]. As in the previous calculations, the kinetic interaction terms set to zero since the two motions are orthogonal.…”

Section: Methyl Torsion and Amine Hydrogen Waggingmentioning

confidence: 99%

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Ab InitioDetermination of the Torsion-Wagging and Wagging-Bending Infrared Band Structure Spectrum of Methylamine

Smeyers

Villa

Senent

1998

Journal of Molecular Spectroscopy

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Section: Methyl Torsion and Amine Hydrogen Waggingmentioning

confidence: 99%

“…The far-infrared (FIR) of methylamine was recorded by Ohashi et al in the region from 40 to 530 cm Ϫ1 (5,6) and from 340 to 640 cm Ϫ1 (7), and by Keglewski et al from 635 to 830 cm Ϫ1 (8). The FIR spectrum of methylamine consists of a highly congested band structure with an intensity maximum around 760 cm…”

Section: Introductionmentioning

confidence: 99%

Ab InitioDetermination of the Torsion-Wagging and Wagging-Bending Infrared Band Structure Spectrum of Methylamine

Smeyers

Villa

Senent

1998

Journal of Molecular Spectroscopy

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“…It is rich in structural features, exhibiting NH 2 and CH 3 stretches and deformations and particularly two large amplitude motions, the torsional motion of the methyl moiety (internal rotation) and the wagging motion of the hydrogen atoms of the amine group (inversion motion), which are of dynamical importance. Because of these features, the methylamine molecule attracted much interest and has been extensively studied experimentally [12][13][14][15] and theoretically. [16][17][18][19][20][21] On these grounds, we thought it will be interesting to assess the performance of ab initio and DFT harmonic calculations combined with anharmonic corrections.…”

Section: Introductionmentioning

confidence: 99%

Fundamental vibrational frequencies and dominant resonances in methylamine isotopologues by ab initio and density functional theory methods

2007

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Ab initio and density functional theory (DFT) calculations were performed for obtaining fundamental vibrational frequencies of methylamine, CH3NH2, and its deuterated variants CH3ND2, CD3NH2, and CD3ND2. The calculations were carried out using the CCSD(T) coupled cluster approximation with cc-pVTZ and cc-pVQZ basis sets, and by the DFT method with the semiempirical hybrid functional B97-1 with polarization consistent pc-2 and pc-3 basis sets. Reasonable performance of the DFT harmonic and ab initio harmonic calculations was found, which improved considerably upon combination of the harmonic fundamental frequencies with anharmonic corrections from the smaller, pc-2, basis. The computed anharmonic fundamental frequencies of methylamine isotopologues agree very well with the experimental values and represent a useful tool for assignment and analysis of the dominant resonances.

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“…The experimental results of the first 40 years of extensive study were summarized in 1987 by Ohashi et al [2], who compiled a data set including far-infrared rotational transitions and ground-state combination differences determined from the fundamental torsional band, as well as microwave data covering a range from 4.6 to 90 GHz. The measurement accuracy for microwave transitions in this data set was about 1.0 MHz due to unresolved quadrupole hyperfine structure [2]. The frequency range of measured rotational transitions was extended by Kreglewski and Wlodarczak [3] up to 470 GHz.…”

Section: Introductionmentioning

confidence: 99%