Microwave Spectrum of Propylene. II. Potential Function for the Internal Rotation of the Methyl Group

1966 ◽  
Vol 45 (6) ◽  
pp. 1984-1990 ◽  
Author(s):  
Eizi Hirota
Keyword(s):  
Internal Rotation ◽  
Potential Function ◽  
Microwave Spectrum ◽  
Methyl Group

Gauche Propanal: Microwave Spectrum and Methyl Barrier

1987 ◽  
Vol 42 (9) ◽  
pp. 957-962 ◽  
Author(s):  
Jeremy Randeil ◽  
A. Peter Cox ◽  
H. Dreizier
Keyword(s):  
Internal Rotation ◽  
Ground State ◽  
Rotational Constant ◽  
Microwave Spectrum ◽  
Methyl Group

The barrier hindering internal rotation of the methyl group was determined by analysing ground-state A, E splittings of rotational lines in the 0+ and 0- torsional states of gauche propanal. The value V3 = 886 (10)cm-1 obtained can be compared with that obtained earlier for the cis rotamer.The A rotational constant has also been determined, its value averaged over the two lowest states being 26248.41 (5) MHz.

scholarly journals Microwave Spectrum of Ethyl Iodid: Internal Rotation Analysis

1980 ◽  
Vol 35 (4) ◽  
pp. 442-446 ◽  
Author(s):  
D. Boucher ◽  
A. Dubrulle ◽  
J. Demaison
Keyword(s):  
Internal Rotation ◽  
Plane Deformation ◽  
Microwave Spectrum ◽  
The Other ◽  
Kcal Mole ◽  
Coriolis Interaction ◽  
Methyl Group ◽  
Rotational Spectra ◽  
First Excited State ◽  
Methyl Torsion

Abstract The rotational spectra of the first excited state of the methyl torsion and the CCI-in plane deformation of CH3CH2I have been studied. A Coriolis interaction between these two modes has been found. Splittings of transitions in the first excited torsional state show that the barrier hindering internal rotation of the methyl group is 3.62 kcal/mole. This value agrees quite well with the value previously reported from Raman studies. It is internally consistent and similar to the other ethyl halides.

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

1996 ◽  
Vol 51 (8) ◽  
pp. 923-932 ◽  
Author(s):  
H. Hartwig ◽  
H. Dreizler
Keyword(s):  
Internal Rotation ◽  
Potential Function ◽  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Rotation Axes ◽  
Direction Cosines ◽  
Rotational Transitions ◽  
Good Agreement

Abstract The microwave spectrum of trans-2,3-dimethyloxirane (CH3CHOCHCH3) in the excited tor-sional states υ17 = 1 and υ33 = 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 V3 and the direction cosines λ g,i 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 V6 was found to be - 0.2600(12) kJ/mol. The value of the parameter V′12 describing the top-top coupling in the potential function (via V′12 sin 3 τ1 sin 3 τ2), was determined to -0.4240(6) kJ/mol.

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