Quadrupole Hyperfine Structure in the Rotational Spectrum of Benzonitrile

1988 ◽  
Vol 43 (3) ◽  
pp. 283-284 ◽  
Author(s):  
K. Vormann ◽  
U. Andresen ◽  
N. Heineking ◽  
H. Dreizler

Abstract We reinvestigated the quadrupole coupling of benzonitrile by an improved technique of microwave Fourier transform (MWFT) spectroscopy and evaluation method. The error of the coupling constants was reduced by one order of magnitude.

1993 ◽  
Vol 48 (12) ◽  
pp. 1219-1222 ◽  
Author(s):  
U. Kretschmer ◽  
H. Dreizler

Abstract We investigated the 33S nuclear quadrupole coupling of thiazole- 33S in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8529.29268 (70) MHz, B = 5427.47098 MHz, and C = 3315.21676 (26) MHz, quartic centrifugal distortion constants and the quadrupole coupling constants of 33S χaa = 7.1708 (61) MHz and χbb= -26.1749 (69) MHz and of 14N χ aa = -2.7411 (61) MHz and χbb = 0.0767 (69) MHz.


1988 ◽  
Vol 43 (7) ◽  
pp. 657-661 ◽  
Author(s):  
N. Heineking ◽  
H. Dreizler

AbstractWe redetermined the rotational and the chlorine-35 and nitrogen-14 nuclear quadrupole coupling constants of 3-chloropyridine. The values are A = 5839.5330(12) MHz, B = 1604.1875(6) MHz, and C = 1258.3121 (5) MHz for the rotational constants, and χaa(Cl) = - 72.255(19) MHz, χbb(Cl) = + 38.500(13) MHz, χcc(Cl) = + 33.755(23) MHz and χaa(N) = - 0.009(13) MHz, χbb(N) = - 3.473(10) MHz, χCC(N) = + 3.482(16) MHz for the chlorine-35 and nitrogen-14 nuclear quadrupole coupling constants, respectively.Application of double resonance modulation technique is shown to greatly simplify the assign­ment of hyperfine structure components even of weak rotational transitions.


1988 ◽  
Vol 43 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Olaf Böttcher ◽  
Dieter H. Sutter

Abstract A microwave Fourier transform study of the rotational spectrum of 3-fluoro-benzonitrile was carried out to study the 14N quadrupole coupling and to give improved rotational constants and centrifugal distortion parameters. In order to fully exploit the high resolution inherent to the experimental technique, frequencies, linewidths, intensities and phases were directly fitted to the observed transient emission signals. The quadrupole coupling constants are discussed in comparison to those of the related molecules 2-fluoro-benzonitrile, 4-fluoro-benzonitrile, and benzonitrile itself. For this comparison a sufficient number of hfs-patterns of the latter molecules was remeasured to derive coupling constants of comparable reliability. The four molecules may be grouped into two pairs. In benzonitrile and in 3-fluoro-benzonitrile the CN-bond shows a smaller deviation from cylindrical symmetry than in 2-and 4-fluoro-benzonitrile.


1989 ◽  
Vol 44 (9) ◽  
pp. 833-836 ◽  
Author(s):  
J.-U. Grabow ◽  
H. Ehrlichmann ◽  
H. Dreizler

Abstract We reinvestigated the rotational spectra of morpholine and N-deutero morpholine with the higher precision of microwave Fourier transform spectroscopy. The rotational, centrifugal, and nitrogen quadrupole coupling constants were improved and the deuterium quadrupole coupling constants determined.


1989 ◽  
Vol 44 (9) ◽  
pp. 841-847 ◽  
Author(s):  
H. Ehrlichmann ◽  
J.-U. Grabow ◽  
H. Dreizler ◽  
N. Heineking ◽  
M. Andolfatto

Abstract We reinvestigated by microwave Fourier transform spectroscopy the rotational spectra of the axial and equatorial isotopomers of piperidine and N-deutero piperidine. The rotational, centrifugal, and nitrogen quadrupole coupling constants were improved, the deuterium quadrupole coupling constants were determined. The principal coupling tensor elements for nitrogen were estimated.


1994 ◽  
Vol 49 (11) ◽  
pp. 1059-1062
Author(s):  
J. Gripp ◽  
U. Kretschmer ◽  
H. Dreizler

Abstract We investigated the 33S nuclear quadrupole coupling in the rotational spectrum of isothiazole in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8275.51880(80) MHz, B = 5767.06181 (40) MHz, and C = 3396.85702(36) MHz, quartic centrifugal distortion constants, and the quadrupole coupling constants χaa (33S) = 8.7015 (57) MHz, χbb(33S) = -32.9696(60) MHz, χaa(14N) = 1.0732(47) MHz and χbb(14N) = -2.4753(46) MHz.


1990 ◽  
Vol 45 (6) ◽  
pp. 807-810 ◽  
Author(s):  
H. Harder ◽  
W. Stahl ◽  
H. Dreizler

AbstractWe reinvestigated the rotational spectra of tert-butyl bromide (CH3)3C79Br and (CH3)3C81Br, with the high precision of microwave Fourier transform spectroscopy. The rotational and quadrupole coupling constants were improved, the centrifugal distortion and bromine spin-rotation constants were determined


1990 ◽  
Vol 45 (9-10) ◽  
pp. 1175-1184 ◽  
Author(s):  
C. Heldmann ◽  
H. Dreizler

Abstract The vibrational ground state microwave spectrum of cyclopropyl isocyanate was investigated in the region from 8.4 to 40 GHz by microwave Fourier transform (MWFT) spectroscopy. The quadru-pole hyperfine structure was resolved and assigned. The quadrupole coupling constants are given. With respect to the data given in the literature up to now, this work led to a more profound description of the pure rotational spectrum. Furthermore, some interesting and surprising results concerning the effect of centrifugal distortion are presented. Compared to hitherto existing investi-gations, these results indicate a more complicated conformational behaviour of cyclopropyl iso-cyanate.


1991 ◽  
Vol 46 (11) ◽  
pp. 989-992 ◽  
Author(s):  
N. Heineking ◽  
J.-U. Grabow ◽  
K. Vormann ◽  
W. Stahl

AbstractNuclear quadrupole hyperfine structures have been resolved in the rotational spectrum of thionyl aniline, C6H5NSO, using pulsed molecular beam microwave Fourier transform spectroscopy. High precision nuclear quadrupole coupling constants, rotational and quartic centrifugal distortion constants have been determined from the analysis of 12 low-J transitions. Coupling constants are χaa = + 1.5730(14) MHz and (χbb - χcc)= -5.6499(13) MHz. rotational constants are A-4026.72i5(4) MHz, B = 860.64732(8) MHz, and C = 709.52027(7) MHz, and centrifugal distortion constants are ΔJ - 36.6(5) Hz, ΔJK= -107.5(20) Hz, ΔK = 703(68) Hz, δJ = 8.1(5) Hz, and δK=111(19) Hz (representation I' used).


1996 ◽  
Vol 51 (10-11) ◽  
pp. 1110-1112 ◽  
Author(s):  
Jens-Uwe Grabow ◽  
Masao Onda ◽  
Helmut Dreizler

Abstract The rotational spectrum of 33S 2,2-dimethylthiirane with its 33S nuclear quadrupole coupling hyperfine structure in the range 8.9 to 20.0 GHz and its analysis is reported. The rotational constants are A = 5507.4663(3), B = 3440.58395(18), and C = 2978.5723(3) MHz. The 33 S quadrupole coupling constants are χaa = -22.6390(23), χbb = 47.1830(50), and χcc = -24.5440(50) MHz.


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