High Resolution Microwave Spectroscopy of Ethyl Vinyl Ether: Accurate Determination of the Methyl Top Internal Rotation Barrier

2000 ◽  
Vol 55 (5) ◽  
pp. 481-485 ◽  
Author(s):  
H. Dreizler ◽  
N. Hansen
Keyword(s):  
Internal Rotation ◽  
Vinyl Ether ◽  
Accurate Determination ◽  
Ethyl Vinyl Ether ◽  
Ethyl Vinyl ◽  
Methyl Group ◽  
Rotational Spectra ◽  
Internal Rotation Barrier ◽  
In Trans

Abstract We have performed an investigation of the internal rotation of the methyl group in trans-cis ethyl vinyl ether by using molecular beam-Fourier transform Microwave (MB-FTMW) spectroscopy. Rotational spectra (up to J = 20) were recorded in the frequency region 4-19 GHz. Due to the internal rotation of the methyl group, some rotational transitions were split and the torsional barrier could be determined to V3 (CH3) = 1074.4(4) cm-1 .

Determination of a High Potential Barrier Hindering Internal Rotation in 2-Methylcyclopentanone and α-Methyl-γ-Butyrolactone by Microwave Fourier Transform Spectroscopy

1992 ◽  
Vol 47 (6) ◽  
pp. 761-764 ◽  
Author(s):  
J. L. Alonso ◽  
N. Heineking ◽  
H. Dreizler ◽  
N. Heineking ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Excited States ◽  
Fourier Transform Spectroscopy ◽  
Vibrationally Excited ◽  
Methyl Group ◽  
Internal Rotation Barrier ◽  
High Potential Barrier ◽  
Method Analysis

AbstractThe microwave spectra of α-methyl-γ-butyrolactone and 2-methylcyclopentanone have been reinvestigated using microwave Fourier transform spectroscopy. A-E splittings due to internal rotation of the methyl group have been observed in the ground and several vibrationally excited states for both molecules. From an internal-axis-method analysis of these splittings, values of the methyl group internal rotation barrier of 2.61 kcal mol-1 for α-methyl-γ-butyrolactone and 2.41 kcal mol-1 for 2-methylcyclopentanone have been obtained.

The Microwave Spectra of m-Xylene and m-Xylene-d10. Determination of the Low Methyl Internal Rotation Barrier

2001 ◽  
Vol 56 (9-10) ◽  
pp. 635-640 ◽  
Author(s):  
C. Thomsen ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Microwave Spectroscopy ◽  
Methyl Groups ◽  
Rotation Barrier ◽  
Rotational Constants ◽  
Moments Of Inertia ◽  
Rotational Spectra ◽  
Internal Rotation Barrier

Abstract The rotational spectra of m-xylene, (CH3)2C6H4 and of m-xylene-d10, (CD3)2C6D4 have been recorded between 6 and 26.5 GHz using pulsed beam Fourier transform microwave spectroscopy. The clue for the assignment of the internal rotation multiplets was the inertial defect derived from the A1A1 species transitions. The rotational constants for m-xylene and m-xylene-d10 are A = 3572.1117(1) MHz / 2896.1195(17) MHz, B = 1761.8621(1) MHz / 1446.0236(15) MHz, C =1197.3943(2) MHz / 988.2357(7) MHz, the barrier to internal rotation of the two methyl groups are V3 = 53.7(16) J/mol / 39.8(5) J/mol, their moments of inertia were assumed to be I∞= 3.14 uÅ2 / 6.28 uÅ2.

Centrifugal Distortion and Ground State Internal Rotation Analysis of the Microwave Spectrum of Dimethylsulfoxide

1983 ◽  
Vol 38 (6) ◽  
pp. 668-675 ◽  
Author(s):  
E. Fliege ◽  
H. Dreizler ◽  
V. Typke
Keyword(s):  
Internal Rotation ◽  
Ground State ◽  
Accurate Determination ◽  
Microwave Spectrum ◽  
Rotation Barrier ◽  
Centrifugal Distortion ◽  
Distortion Analysis ◽  
Internal Rotation Barrier ◽  
Centrifugal Distortion Constants

The torsional Fine structure of dimethylsulfoxide has been reinvestigated with MWFT-spectroscopy. The higher resolution results in a more accurate determination of the internal rotation barrier V3. The centrifugal distortion analysis is extended to sixth order. The prediction of lines is excellent, but some centrifugal distortion constants are poorly determined

Sign in / Sign up

Export Citation Format

Share Document