Nitrogen Quadrupole Coupling in the Rotational Spectrum of l-Isocyanoprop-2-yne, HC ≡ CCH2NC

1990 ◽  
Vol 45 (8) ◽  
pp. 986-988 ◽  
Author(s):  
M. Krüger ◽  
H. Dreizler

AbstractThe rotational spectrum of l-isocyanoprop-2-yne, HC≡CCH2NC, has been measured in the vibrational ground state by microwave Fourier transform spectroscopy from 5 to 26.5 GHz. The nuclear quadrupole hyperfine splittings due to 14N have been analysed to obtain the coupling constants χaa = 290.3(78) kHz, χbb = 10.6(80) kHz and χcc= -300.9(80) kHz

1983 ◽  
Vol 38 (9) ◽  
pp. 1015-1021
Author(s):  
W. Kasten ◽  
H. Dreizler ◽  
Brian E. Job ◽  
John Sheridan

Abstract The microwave spectra of CF3CN, CH2FCN, CHDFCN, CD2FCN and CHF2CN have been measured and analysed. The nuclear quadrupole hyperfine splittings due to 14N have been measured by Microwave Fourier Transform spectroscopy. The nuclear quadrupole coupling constants, transformed to the bonding axis systems of the C-C ≡ N groups, are shown to be in accord with structural predictions of the p-electron populations at the nitrogen atom.


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.


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.


1972 ◽  
Vol 27 (6) ◽  
pp. 1011-1014 ◽  
Author(s):  
F Scappini ◽  
A Guarnieri

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.


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 (8-9) ◽  
pp. 755-757 ◽  
Author(s):  
N. Heineking ◽  
M. Andolfatto ◽  
C. Kruse ◽  
W. Eberstein ◽  
H. Dreizler

Abstract Employing the high resolution of microwave Fourier transform spectroscopy, we investigated the lowest rotational transitions of fluoro-, bromo-, and iodoacetylene-d. Along with the rotational, centrifugal distortion, halogen nuclear quadrupole, and halogen spin-rotation coupling constants, we determined the deuterium quadrupole coupling constants of bromo-and iodoacetylene-d. For fluoroacetylene-d, we redetermined the deuterium nuclear quadrupole coupling constants with higher accuracy.


1987 ◽  
Vol 42 (1) ◽  
pp. 83-86 ◽  
Author(s):  
Nils Heineking ◽  
Helmut Dreizler

The quadrupole coupling of the two nitrogen nuclei was investigated by microwave Fourier transform spectroscopy. The results contribute to a comparison of substituent effects in different pyridine derivatives.


1992 ◽  
Vol 47 (10) ◽  
pp. 1067-1072 ◽  
Author(s):  
Michael Krüger ◽  
Helmut Dreizler

AbstractThe barrier heights (V3) hindering methyl internal rotation were determined with microwave Fourier transform spectroscopy from the ground vibrational state for the title molecules and found to be V3 = 3.336(52) kcal/mol for ethyl isocyanide, V3 > 3.1 kcal/mol for iso-propyl isocyanide, V3 = 2.894(23) kcal/mol for gauche-n-propyl isocyanide and V3 = 2.954(22) kcal/mol for transn- propyl isocyanide. The quadrupole coupling constants of iso-propyl isocyanide are χaa = 179.3(31) kHz, χbb = -140(15) kHz and χcc - 39(15) kHz; the constants of trans-n-propyl isocyanide were determined to be χaa = 268.1 (71) kHz, χbb = - 108(23) kHz and χcc = - 160(23) kHz.


1994 ◽  
Vol 49 (11) ◽  
pp. 1063-1066
Author(s):  
S. R. Huber ◽  
A. Bauder

Abstract The rotational spectrum of N-methylpyrrole has been measured with pulsed nozzle Fourier transform microwave spectrometers between 6 and 38 GHz. The quadrupole hyperfine structure due to 14N has been reanalyzed in the A (m = 0) state o f the methyl internal rotation. Improved rotational constants, centrifugal distortion constants, and quadrupole coupling constants have been simultaneously determined from the measured transition frequencies in an iterative least-squares fit.


1986 ◽  
Vol 41 (6) ◽  
pp. 835-854
Author(s):  
W. Kasten ◽  
H. Dreizler ◽  
R. L. Kuczkowski ◽  
M. Soltis LaBarge

The microwave ground state spectra of methylphosphine-borane-(11B) and methylphosphinetrideuteroborane-(11B) have been measured by microwave Fourier transform spectroscopy and analysed for 11B-nuclear quadrupole hyperfine splittings and CH3 and BH3 torsion fine structure. As high J transitions were measured a centrifugal distortion analysis was necessary. The B-P bond order is discussed.


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