Microwave Spectrum, Dipole Moment and Centrifugal Distortion Constants of 1,2,4-Trifluorobenzene

1978 ◽  
Vol 44 (2) ◽  
pp. 598-601 ◽  
Author(s):  
S. Doraiswamy ◽  
S. D. Sharma
Keyword(s):  
Dipole Moment ◽  
Microwave Spectrum ◽  
Centrifugal Distortion ◽  
Centrifugal Distortion Constants

Microwave spectrum, dipole moment, and centrifugal distortion constants of 1,2,3,5-tetrafluorobenzene

1977 ◽  
Vol 55 (14) ◽  
pp. 1211-1217 ◽  
Author(s):  
S. D. Sharma ◽  
S. Doraiswamy
Keyword(s):  
Dipole Moment ◽  
Bond Length ◽  
Benzene Ring ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Centrifugal Distortion ◽  
Dry Ice ◽  
Type Spectrum ◽  
Centrifugal Distortion Constants

The microwave spectrum of 1,2,3,5-tetrafluorobenzene has been studied at dry ice temperature in the frequency region of 8 to 12.4 GHz. The molecule is highly asymmetric (κ = 0.001129) and exhibits an a-type spectrum. The analysis of the spectrum has been carried out to obtain the following Watson's eight determinable parameters: [Formula: see text], [Formula: see text], [Formula: see text], τ′aaaa = −1.30 ± 1.26 kHz, τ′bbbb = −4.05 ± 0.40 kHz, τ′cccc = −0.75 ± 0.40 kHz, τ1 = −15.21 ± 1.34 kHz and [Formula: see text]. The dipole moment of the molecule is found to be 1.46 ± 0.06 D. The calculated values obtained from INDO and CNDO approximations are 1.73 and 1.64 D, respectively. The benzene ring appears to have undergone a distortion if we assume that C(sp2)—F bond length is around 135 pm.

The Microwave Spectrum and Dipole Moment of Hexafluoropropanone

1991 ◽  
Vol 46 (3) ◽  
pp. 229-232 ◽  
Author(s):  
J.-U. Grabow ◽  
N. Heineking ◽  
W. Stahl
Keyword(s):  
Fourier Transform ◽  
Dipole Moment ◽  
Molecular Beam ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Fourier Transform Spectrometer ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Centrifugal Distortion Constants

AbstractWe recorded the microwave spectrum of hexafluoropropanone between 7 and 15 GHz using a pulsed molecular beam microwave Fourier transform spectrometer. The rotational constants were determined to be A = 2181.71980(14) MHz, B= 1037.22930(7) MHz, C = 934.89233(8) MHz, the quartic centrifugal distortion constants are D'J= 0.07378 (39) kHz, D'JK = 0.10002(75) kHz, D'K = -0.07269(266) kHz, δ'J = 0.00623(29) kHz and R' 6= 0.00755(12) kHz. Stark effect measurements yielded a dipole moment μ = μb= 0.3949 (18) D

Microwave Spectrum of Methane-d2, CH2D2

1975 ◽  
Vol 53 (19) ◽  
pp. 2023-2028 ◽  
Author(s):  
Eizi Hirota ◽  
Misako Imachi
Keyword(s):  
Dipole Moment ◽  
Microwave Spectrum ◽  
Normal Coordinate Analysis ◽  
Centrifugal Distortion ◽  
Normal Coordinate ◽  
Rotational Constants ◽  
Microwave Spectrometer ◽  
Rotational Transitions ◽  
Centrifugal Distortion Constants

Three rotational transitions of methane-d2 were observed by a source-modulation microwave spectrometer. The two differences in the rotational constants, A – C and B – C, were determined to be 37 555.758 and 13 664.280 MHz, respectively, from the observed frequencies of 110 ← 101 and 211 ← 202 after correcting for the centrifugal distortion effects. The centrifugal distortion constants were evaluated by a normal coordinate analysis. The dipole moment of CH2D2 was determined to be 0.014 ± 0.005 D, by comparing the intensity of 211 ← 202 with that of an oxygen line.

The Microwave Spectrum, Dipole Moment, and Structure of Glycidol

1975 ◽  
Vol 53 (15) ◽  
pp. 2247-2251 ◽  
Author(s):  
W. V. F. Brooks ◽  
K. V. L. N. Sastry
Keyword(s):  
Hydrogen Bonding ◽  
Dipole Moment ◽  
Hydrogen Atom ◽  
Microwave Spectrum ◽  
Centrifugal Distortion ◽  
Total Dipole Moment ◽  
Hindered Rotation ◽  
Rotational Constants ◽  
Microwave Spectra ◽  
Centrifugal Distortion Constants

The microwave spectra of glycidol [Formula: see text] and its deuterated (—OD) form have been studied in the range 8–40 GHz. The rotational (in MHz) and centrifugal distortion constants (in kHz) of glycidol are: A = 10 347.87, B = 4102.36, C = 3781.95; ΔJ = 2.38, ΔJK = −311, ΔK = 5.2, δJ = 0.3159, δK = −9.76. The rotational constants and distortion constants of glycidol (OD) are A = 10 010.31, B = 4056.73, C = 3717.02; ΔJ = 2.53, ΔJK = 197, ΔK = 7.7,δJ = 0.3532,δK = −7.19. The dipole moment components of the normal molecule in Debye units are μa = 0.61, μb = 1.20, μc = 0.52, and the total dipole moment is 1.44 D.A structure is derived with the alcoholic hydrogen atom close (2.5 Å) to the ring oxygen. The structure and the absence of signs of free or hindered rotation, can be accounted for by hydrogen bonding between the proton and the ring oxygen.

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