Microwave Spectrum and Barrier to Internal Rotation of 5-Methylisoxazole

1975 ◽  
Vol 30 (10) ◽  
pp. 1279-1281 ◽  
Author(s):  
P. J. Mjöberg ◽  
W. M. Ralowski ◽  
S. O. Ljunggren
Keyword(s):  
Internal Rotation ◽  
Ground State ◽  
Microwave Spectrum ◽  
State Transitions ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Methyl Group

Abstract The ground state rotational spectrum of 5-methylisoxazole has been studied in the region 18 000 -36 000 MHz. The A and E state transitions have been assigned.The rotational constants are A = 9230.831 MHz, B = 3559.334 MHz and C = 2610.255 MHz and the three-fold barrier to internal rotation of the methyl group was calculated to be 777.2 ± 5.5 cal mol-1 .

The Microwave Spectrum of 2,6-Lutidine, Analysis of Internal Rotation and 14 N Hyperfine Structure

1993 ◽  
Vol 48 (11) ◽  
pp. 1093-1101 ◽  
Author(s):  
C. Thomsen ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Hyperfine Structure ◽  
Internal Rotation ◽  
Molecular Beam ◽  
Microwave Spectrum ◽  
Methyl Groups ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Moments Of Inertia ◽  
Nuclear Quadrupole

Abstract The rotational spectrum of 2,6-lutidine, (CH3)2C5H3N, has been recorded between 6 and 26.5 GHz using pulsed molecular beam microwave Fourier transform spectroscopy. The rotational constants are A = 3509.7139(84) MHz, B = 1906.8639(101) MHz, and C = 1254.6215(14) MHz, the barrier to internal rotation of the two methyl groups is V3 = 1.1752 kJ/mol, their moments of inertia were found to be Iα = 3.0808(9) uÅ2 . The nitrogen nuclear quadrupole constants are χaa = +1.600(5) MHz, χbb = -4.572(3) MHz and χcc = +2.972(5) MHz.

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.

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.

Determination of a High Potential Barrier Hindering Internal Rotation from the Analysis of the Ground State Spectrum: The Case of Ethyl Cyanide

1980 ◽  
Vol 35 (11) ◽  
pp. 1136-1141 ◽  
Author(s):  
D. Boucher ◽  
A. Dubrulle ◽  
J. Demaison ◽  
H. Dreizler
Keyword(s):  
Internal Rotation ◽  
Potential Barrier ◽  
Ground State ◽  
High Potential ◽  
State Transitions ◽  
Rotational Spectrum ◽  
Barrier Potential ◽  
High Potential Barrier

Abstract The ground state rotational spectrum of ethyl cyanide has been reinvestigated between 8 and 250 GHz. The barrier potential V3 is calculated from 11 high J, ground state transitions which were found split into doublets. V3 is 3007 cal/mole, assuming Iα = 3.167 u Å2 and ∢ (i,a) = 48.65°. The splittings of the K-doublet transitious have also been analyzed.

A Reinvestigation of the Rotational Spectrum of 2-Chloropropene

1983 ◽  
Vol 38 (11) ◽  
pp. 1231-1237 ◽  
Author(s):  
E. Fliege ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Ground State ◽  
Fourier Transform Spectroscopy ◽  
Microwave Spectrum ◽  
Rotational Spectrum ◽  
Isotopic Species ◽  
Quadrupole Coupling

The microwave spectrum of 2-chloropropene was reinvestigated using microwave Fourier transform spectroscopy. For the two isotopic species CH3C35Cl=CH2 and CH3C37Cl=CH2 the chlorine quadrupole coupling was determined with higher accuracy. The barrier to internal rotation was determined from the ground state. For comparison the first excited torsional state of CH3C35Cl=CH2 was remeasured and reanalysed

The Microwave Spectrum of Disilylsulfide

1978 ◽  
Vol 33 (4) ◽  
pp. 500-501 ◽  
Author(s):  
K.-F. Dössel ◽  
D. H. Sutter
Keyword(s):  
Internal Rotation ◽  
Microwave Spectrum ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Rotation Parameters

We report an analysis of the rotational spectrum of (SiH3)2S, leading to the rotational constants A, B, C and the internal rotation parameters V3, θ and Iα.

Microwave Spectrum and Quadrupole Coupling Constants of Orthochloropyridine

1972 ◽  
Vol 27 (6) ◽  
pp. 1011-1014 ◽  
Author(s):  
F Scappini ◽  
A Guarnieri
Keyword(s):  
Ground State ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract The rotational spectrum of 2-chloropyridine was measured in the region between 8-40 GHz. The rotational constants for the vibrational ground state are: A = 5872.01 ± 0.02 MHz, B = 1637.82 ± 0.02 MHz, C=1280.51 ± 0.02 MHz. The value 0.0385 amu · A2 of the inertia defect indicates a planar nuclear frame. From the hyper-fine splittings of the rotational lines the nuclear quadrupole coupling constants of 35Cl were determined. The values are:χaa = 70.79 ± 0.17 MHz, χbb = 39.01 ± 0.45 MHz, χcc = 31.78 ± 0.62 MHz.

The Ground State Microwave Spectrum and Dipole Moment of 2-Isocyano-Propane

1989 ◽  
Vol 44 (7) ◽  
pp. 680-682 ◽  
Author(s):  
Michael Krüger ◽  
Helmut Dreizler
Keyword(s):  
Fourier Transform ◽  
Dipole Moment ◽  
Ground State ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Total Dipole Moment ◽  
Rotational Constants ◽  
Centrifugal Distortion Constants

Abstract The ground state rotational spectrum of 2-isocyano-propane is assigned. The rotational constants and the quartic centrifugal distortion constants are determined by Microwave Fourier Transform (MWFT) Spectroscopy. The analysis of the Stark effect leads to a total dipole moment of 4.055(1) D.

Extended Analysis of the Rotational Spectrum of HCCF

1989 ◽  
Vol 44 (2) ◽  
pp. 131-138 ◽  
Author(s):  
F. Rohwer ◽  
R. Hinze ◽  
A. Guarnieri
Keyword(s):  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Rotational Spectrum ◽  
Bending Vibrations ◽  
Rotational Constants ◽  
Extended Analysis

Abstract The microwave spectrum of fluoroacetylene (HCCF) has been measured in the frequency region 35 -260 GHz. Rotational constants of the ground state and rotational as well as rotation-vibrational interaction constants of several excited states of the C - C - H (ν4) and the C - C - F (ν5) bending vibrations have been obtained.

scholarly journals The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

1985 ◽  
Vol 40 (9) ◽  
pp. 913-919
Author(s):  
Juan Carlos López ◽  
José L. Alonso
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Ground State ◽  
Principal Axis ◽  
Microwave Spectrum ◽  
Average Intensity ◽  
Ring Conformation ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

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