Notizen: A Pulsed Molecular Beam Microwave Fourier Transform Spectrometer with Parallel Molecular Beam and Resonator Axes

Grabow, Jens‐Uwe; Stahl, Wolfgang

doi:10.1515/zna-1990-0817

Cited by 331 publications

(149 citation statements)

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“…Further investigations [2] utilized the high resolution of molecular beam Fourier transform microwave spectroscopy [3,4], With these precise measurements the value for V 3 was improved, additionally the moment of inertia I T i of the methyl group i and the angles between the torsion axis and the principal axes of inertia g were determined by an analysis of the internal rotation splittings. The angle x t labels the internal rotation of the top i, in the literature also often denoted as a.…”

Section: Introductionmentioning

confidence: 99%

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

Hartwig

Dreizler

1996

Zeitschrift Für Naturforschung A

380

331

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The microwave spectrum of trans-2,3-dimethyloxirane (CH 3 CHOCHCH 3 ) in the excited torsional states u 17 = 1 and v i3 -1 has been measured in the range from 8 to 26 GHz and assigned. An analysis of internal rotation splittings of the observed rotational transitions was performed using the internal axis method (or "combined axis method") with a newly developed program accounting for the top-top coupling. The threefold hindering potential V 3 and the direction cosines /. g of the internal rotation axes i with respect to the principal inertia axes g are in a good agreement with the ground state values. Additionally, the sixfold hindering parameter V t was found to be -0.2600(12) kJ/mol. The value of the parameter V[ 2 describing the top-top coupling in the potential function (via V[ 2 sin3r! sin3i 2 ), was determined to -0.4240(6) kJ/mol.

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Section: Introductionmentioning

confidence: 99%

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

Hartwig

Dreizler

1996

Zeitschrift Für Naturforschung A

380

331

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“…Each line is split due to the Doppler effect by 45 kHz, the line width is 1 kHz (HWHH). Recording conditions: 100 ns sample interval, 8 K data points, extended with 24 k zeros prior to Fourier transformation, 1000 experiment cycles, 6 Hz experiment repetition rate [26],…”

Section: Resultsmentioning

confidence: 99%

“…Our laboratory followed with an improved waveguide MWFT spectrometer [24] shortly later. The beam instrument was recently improved in our laboratory for a scanning version [25] and a version with increased resolution [26]. For details of our spectrometers see [24,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44],…”

Section: Consequences For the Experimentsmentioning

confidence: 99%

Contribution of Microwave Fourier Transform Spectroscopy to the Investigation of Nuclear Quadrupole Coupling

Dreizler

1992

Zeitschrift Für Naturforschung A

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“…42 In the 48-70 GHz mm-wave region the spectra were recorded using a free-jet, Stark-modulated absorption spectrometer at Monash University, that has been modified with solid state sweep oscillator sources. 43 The three instruments have been described extensively; [40][41][42][43] therefore, only brief experimental details are given here. The solid sample was inserted inside a reservoir located at the nozzle exit and heated at 110-180 1C in the Hannover and Monash spectrometers.…”

Section: Experimental Methodsmentioning

confidence: 99%

Conformational steering in dicarboxy acids: the native structure of succinic acid

Jahn

Méndez

Nair

et al. 2015

Phys. Chem. Chem. Phys.

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The torsional freedom of the carbon backbone and hydroxyl groups of succinic acid, an important platform chemical fi nding numerous industrial applications as well as being the focus of considerable research in atmospheric science, is elucidated. The question of the potential presence of numerous conformers is answered by an unambiguous identifi cation of the structural and molecular properties using microwave and millimeter wave spectroscopy. The precise spectroscopic data provides evidence that the anomalous tendency of "folding the methylene unit" is favoured. Succinic acid, a dicarboxylic acid molecule, has been investigated spectroscopically with computational support to elucidate the complex aspects of its conformational composition. Due to the torsional freedom of the carbon backbone and hydroxy groups, a large number of potentially plausible conformers can be generated with an indication that the gauche conformer is favored over the trans form. The microwave and millimeter wave spectra have been analyzed and accurate spectroscopic constants have been derived that correlate best with those of the lowest energy gauche conformer. For an unambiguous conformational identification measurements were extended to the monosubstituted isotopologues, precisely determining the structural properties. Besides bond distances and angles, particularly the dihedral angle has been determined to be 67.76(11)1, confirming the anomalous tendency of the methylene units to favor gauche conformers when a short aliphatic segment is placed between two carbonyl groups.

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Notizen: A Pulsed Molecular Beam Microwave Fourier Transform Spectrometer with Parallel Molecular Beam and Resonator Axes

Abstract: We report on first experiences with a pulsed molecular beam microwave Fourier transform spectrometer with parallel molecular beam and resonator axes. This setup shows up a high resolution and sensitivity.

Cited by 331 publications

References 0 publications

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

Contribution of Microwave Fourier Transform Spectroscopy to the Investigation of Nuclear Quadrupole Coupling

Conformational steering in dicarboxy acids: the native structure of succinic acid

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