An ab initio structural and spectroscopic study of acetone—An analysis of the far infrared torsional spectra of acetone-h6 and -d6

Smeyers, Yves G.; Senent, María Luisa; Botella, V.; Moule, D. C.

doi:10.1063/1.464157

Cited by 95 publications

(80 citation statements)

References 32 publications

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“…Because of the vectorial nature of the spin functions, the nuclear statistical weights for each symmetry coincide with those determined for the G 36 molecules. 26 Finally, the populations are given by a Boltzmann statistics.…”

Section: Theorymentioning

confidence: 99%

“…23 Fully and partially optimized ab initio calculations can be applied to verify the assignment of IR and Raman spectra. This technique was first employed for a set of molecules showing the G 36 symmetry and two C 3v symmetrical rotors such as thioacetone, 25 acetone, 26 biacetyl, 27 dimethyl-ether, 28,29 dimethyl-sulphide, 30 and butenes. 31 For that purpose, two and three dimension models were used.…”

Section: Introductionmentioning

confidence: 99%

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Ab initio calculations and analysis of the torsional spectra of dimethylamine and dimethylphosphine

Senent

Smeyers

1996

The Journal of Chemical Physics

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In the present paper, ab initio calculations at MP2/RHF level are performed with different basis sets 6-31G(d,p), 6-311G(d, p), and 6-311(d f ,p) to determine the potential energy functions, the kinetic parameters, and the dipole moment components as a function of the double methyl rotation in dimethylamine ͑DMA͒ and dimethylphosphine ͑DMP͒. From the potential energy and kinetic parameters, the torsional energy levels and torsional functions are determined, and from the dipole moment variations, the far infrared spectra are synthesized by calculating both the frequencies and the intensities. The results are in relatively good agreement with experimental spectra. Calculations confirm the assignments performed with the experimental potentials fitted with only five terms. The calculations, however, allow to reassign the observed band at 239.8 cm Ϫ1 in DMA and at 177.2 cm Ϫ1 in DMP to the superimposition of two different transitions: the 03→04 third sequence and an 10→11 vibrationally excited fundamental.

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Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ab initio calculations and analysis of the torsional spectra of dimethylamine and dimethylphosphine

Senent

Smeyers

1996

The Journal of Chemical Physics

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“…9,10 The effect of the O → S substitution is thus detailed, as it was done in previous papers where couples of analogs were treated and compared. [34][35][36] …”

Section: Introductionmentioning

confidence: 99%

Theoretical spectroscopic characterization at low temperatures of detectable sulfur-organic compounds: Ethyl mercaptan and dimethyl sulfide

Senent

Puzzarini

Domı́nguez-Gómez

et al. 2014

The Journal of Chemical Physics

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Microwave and ab initio studies of rare gas-methane van der Waals complexes J. Chem. Phys. 120, 9047 (2004); 10.1063/1.1691743 This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Highly correlated ab initio methods are used for the spectroscopic characterization of ethyl mercaptan (CH 3 CH 2 32 SH, ETSH) and dimethyl sulfide (CH 3 32 SCH 3 , DMS), considering them on the vibrational ground and excited torsional states. Since both molecules show non-rigid properties, torsional energy barriers and splittings are provided. Equilibrium geometries and the corresponding rotational constants are calculated by means of a composite scheme based on CCSD(T) calculations that accounts for the extrapolation to the complete basis set limit and core-correlation effects. The ground and excited states rotational constants are then determined using vibrational corrections obtained from CCSD/cc-pVTZ force-field calculations, which are also employed to determine anharmonic frequencies for all vibrational modes. CCSD(T) and CCSD force fields are employed to predict quartic and sextic centrifugal-distortion constants, respectively. Equilibrium rotational constants are also calculated using CCSD(T)-F12. The full-dimensional anharmonic analysis does not predict displacements of the lowest torsional excited states due to Fermi resonances with the remaining vibrational modes. Thus, very accurate torsional transitions are calculated by solving variationally two-dimensional Hamiltonians depending on the CH 3 and SH torsional coordinates of ethyl mercaptan or on the two methyl groups torsions of dimethyl-sulfide. For this purpose, vibrationally corrected potential energy surfaces are computed at the CCSD(T)/aug-cc-pVTZ level of theory. For ethyl mercaptan, calculations show large differences between the gauche (g) and trans (t) conformer spectral features. Interactions between rotating groups are responsible for the displacements of the g-bands with respect to the t-bands that cannot therefore be described with one-dimensional models. For DMS, the CCSD(T) potential energy surface has been semi-empirically adjusted to reproduce experimental data. New assignments are suggested for the methyl torsion bands of ETSH and a reassignment is proposed for the infrared bands of DMS (0 3 → 0 4 and 1 0 → 1 1). Our accurate spectroscopic data should be useful for the analysis of the microwave and far infrared spectra of ETSH and DMS recorded, at low temperatures, either in laboratory or in the interstellar medium.

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“…If we denote by P the permutation character of this action, then we have P = (12,3,6,9,8,5, 0, 0, 0, 4, 1, 1, 2, 2). (3.3)…”

Section: Determination Of Character Tablementioning

confidence: 99%

“…Smeyers in [8] and others in [10,12,13] list among the areas of application large amplitude vibrations in spectroscopy of small organic molecules.…”

Section: Introductionmentioning

confidence: 99%

The full nonrigid group theory for trimethylamine

Hamadanian

Ashrafi

2000

International Journal of Mathematics and Mathematical Sciences

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The nonrigid molecule group theory (NRG) in which the dynamical symmetry operations are defined as physical operations is a new field in chemistry. Smeyers in a series of papers applied this notion to determine the character table of restricted NRG of some molecules. In this note, a simple method is described by means of which it is possible to calculate character tables for the symmetry group of molecules consisting of a number of methyl groups attached to a rigid framework. We study the full NRG of trimethylamine N(CH 3 ) 3 and prove that it is a group of order 1296 with 28 conjugacy classes. The method can be generalized to apply to other nonrigid molecules. The full nonrigid (f-NRG) molecule group theory is seen to be used advantageously to study the internal dynamics of such molecules.2000 Mathematics Subject Classification: 92E10.

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An ab initio structural and spectroscopic study of acetone—An analysis of the far infrared torsional spectra of acetone-h6 and -d6

Cited by 95 publications

References 32 publications

Ab initio calculations and analysis of the torsional spectra of dimethylamine and dimethylphosphine

Ab initio calculations and analysis of the torsional spectra of dimethylamine and dimethylphosphine

Theoretical spectroscopic characterization at low temperatures of detectable sulfur-organic compounds: Ethyl mercaptan and dimethyl sulfide

The full nonrigid group theory for trimethylamine

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