Internal Rotation in Completely Asymmetric Molecules. I. A General Theory and Analysis of the Microwave Rotational Spectrum of CH2DCOH, CD2HCOH, and CHOOCH2D

1963 ◽  
Vol 38 (2) ◽  
pp. 540-550 ◽  
Author(s):  
C. R. Quade ◽  
Chun C. Lin
Keyword(s):  
General Theory ◽  
Internal Rotation ◽  
Rotational Spectrum ◽  
Microwave Rotational Spectrum

Mikrowellenspektrum, Hinderungspotential der internen Rotation und Dipolmoment des para-Fluortoluols

1965 ◽  
Vol 20 (12) ◽  
pp. 1682-1686 ◽  
Author(s):  
Heinz Dieter Rudolph ◽  
Helmut Seiler
Keyword(s):  
Dipole Moment ◽  
Internal Rotation ◽  
Absorption Lines ◽  
Type I ◽  
Rotational Spectrum ◽  
Rotation Barrier ◽  
Rotational Constants ◽  
Methyl Group ◽  
Microwave Rotational Spectrum ◽  
Internal Rotation Barrier

The microwave rotational spectrum of para-fluoro-toluene has been investigated in the region from 7 to 31 kmc/s. The three types of absorption lines to be expected in the case of a molecule of this type, i. e. with a very low sixfold barrier hindering the internal rotation of the methyl group, have been found: m=0, | m | ≠ 0, 3 n, | m | = 3 n. From the lines m=0 the rotational constants and the dipole moment, (1.96 ± 0.02) D, have been deduced; from the lines |m|=3 the internal rotation barrier could be calculated as V6=13.82 cal/mole. This V6 is compared with the values found for similar molecules.

scholarly journals Mikrowellenspektrum, Hinderungspotential der internen Rotation, Quadrupolkopplungskonstanten und Dipolmoment des 2-Methyl-Pyridins

1970 ◽  
Vol 25 (1) ◽  
pp. 25-35 ◽  
Author(s):  
H. Dreizler ◽  
H.D. Rudolph ◽  
H. Mäder
Keyword(s):  
Dipole Moment ◽  
Hyperfine Structure ◽  
Internal Rotation ◽  
Excited States ◽  
Stark Effect ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Microwave Rotational Spectrum ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract The microwave rotational spectrum of 2-methyl-pyridine (a-picoline) has been investigated in the region from 6 to 30 kmc/s. From the three lowest states of internal rotation m=0, 1, 2 the three-and sixfold components V3 and V6 of the potential barrier hindering the internal rotation have been determined to be V3= (258,4 ± 0,1) cal/mole and V6=(-11,8± 0,1) cal/mole. From the splitting of low-J lines m=0 the nuclear quadrupole coupling constants for the 14N nucleus have been derived as χaa= (-0,33 ± 0,02) mc/s, χbb = (-2,86 ± 0,02) mc/s, χcc = (+3,19 ± 0,02) mc/s. The hyperfine structure of rotational transitions in excited states of internal rotation could also be accounted for with these coupling constants. The dipole moment components derived from Stark-effect measurements in the ground torsional state m = 0 are μa = (0,72 ± 0,01) Debye and μb - (1,71 ± 0,02) Debye.

Mikrowellenspektrum, Hinderungspotential der internen Rotation und Dipolmoment des Toluols

1967 ◽  
Vol 22 (6) ◽  
pp. 940-944 ◽  
Author(s):  
H. D. Rudolph ◽  
H. Dreizler ◽  
A. Jaeschke ◽  
P. Wendung
Keyword(s):  
Heat Capacity ◽  
Dipole Moment ◽  
Internal Rotation ◽  
Solid Phase ◽  
Heat Capacity Data ◽  
Rotational Spectrum ◽  
Rotation Barrier ◽  
Microwave Rotational Spectrum ◽  
Internal Rotation Barrier ◽  
Capacity Data

The microwave rotational spectrum of toluene has been investigated in the region from 8 to 23 GHz. The three types of absorption lines to be expected in the case of a molecule of this symmetry with a very low sixfold barrier hindering internal rotation of the methyl top have been found: m=0; |m|≠ 0, 3 n; | m | = 3 n. From the lines m= 0 the rotational constants and the dipole moment (0.375 ± 0.01 D) have been determined; from the lines 1 |m|=3 the internal rotation barrier could be calculated as V60 = (13.94 ± 0.1) cal/mole. This value is discussed and compared with the very much larger value derived from solid-phase heat capacity data.

Hinderungspotential der internen Rotation, Dipolmoment und Quadrupolkopplungskonstanten aus dem Mikrowellenspektrum des 4-Methyl-Pyridins

1967 ◽  
Vol 22 (11) ◽  
pp. 1738-1743 ◽  
Author(s):  
H. D. Rudolph ◽  
H. Dreizler ◽  
H. Seiler
Keyword(s):  
Dipole Moment ◽  
Internal Rotation ◽  
Potential Barrier ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
A Value ◽  
Microwave Rotational Spectrum ◽  
Quadrupole Coupling ◽  
Substituted Toluenes ◽  
Nuclear Quadrupole

The microwave rotational spectrum of 4-methyl-pyridine (γ-picoline) has been investigated in the region from 8 to 37 GHz. The three types of lines to be expected for a molecule of this symmetry and with a very low sixfold barrier hindering internal rotation of the methyl top have been found: m=0; | m | ≠0, ≠ 3 n; | m |=3 n. From low-/ lines m=0 (a-type transitions) the rotational constants A′ (less methyl top) =6 082.145, B=2 524.850, C=1 783.991 MHz, the dipole moment μα=2.70 D, and the nuclear quadrupole coupling constants for the 14N nucleus χaa= —4.82, χbb—χcc= —2.8 MHz have been determined. From the wide splitting of the lines | m | = 3, | K | = 1 the potential barrier has been derived as V6=13.51 cal/mole, a value which is very close to those previously deduced for toluene and para-substituted toluenes.

Rotational spectrum, structure and internal rotation in CH3CCl3

2008 ◽  
Vol 247 (2) ◽  
pp. 160-166 ◽  
Author(s):  
L. Margulès ◽  
M. Carvajal ◽  
J. Demaison
Keyword(s):  
Internal Rotation ◽  
Rotational Spectrum ◽  
Spectrum Structure
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