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1996 (1)
1992 (2)
1990 (1)
1Author    A. D. Gordeev, G. B. Soifer, A. P. ZhukovRequires cookie*
 Title    C1 NQR and Molecular Motion in Solid C 6 X 5 C1 (X = H, F)  
 Abstract    The 35 C1 NQR frequency and spin-lattice relaxation time of solid chlorobenzene and chloro-pentafluorobenzene at temperatures from 77 K to the melting points have been measured and explained by thermoactivated librations and reorientations of the molecules around the normal to their plane. The activation energies of these motions have been estimated. 
  Reference    Z. Naturforsch. 47a, 330—332 (1992); received July 18 1991 
  Published    1992 
  Keywords    NQR spectroscopy, Molecular motion, Benzene derivatives 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0330.pdf 
 Identifier    ZNA-1992-47a-0330 
 Volume    47 
2Author    R. Blinc, J. SeligerRequires cookie*
 Title    2 D Methods in NQR Spectroscopy  
 Abstract    The application of two-dimensional spectroscopy to nuclear quadrupole resonance (NQR) is reviewed with special emphasys on spin 3/2 nuclei. A new two-dimensional level crossing double resonance NQR nutation technique based on magnetic field cycling is described. This technique allows for a determination of both the electric quadrupole coupling constant and the asymmetry parameter for spin 3/2 nuclei in powdered samples even in cases where the quadrupolar signals are too weak to be observed directly. It works if the usual double resonance conditions are met, i.e. if the spin-lattice relaxation times are not too short if the quadrupolar nuclei are dipolarly coupled to "strong" nuclei. Variations of this techique can be also used for 2 D "exchange" NQR spectroscopy and NQR imaging. 
  Reference    Z. Naturforsch. 47a, 333—341 (1992); received July 27 1991 
  Published    1992 
  Keywords    2D methods, NQR spectroscopy, Double resonance 
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 TEI-XML for    default:Reihe_A/47/ZNA-1992-47a-0333.pdf 
 Identifier    ZNA-1992-47a-0333 
 Volume    47 
3Author    A. D. Gordeev, A. N. Osipenko, G. B. SoiferRequires cookie*
 Title    C1 NQR in Solid Trichloroacetyl Halides  
 Abstract    By 35 C1 NQR the temperature dependences of the resonance frequencies and spin4attice relax-ation times for the 35 C1 nuclei have been studied in solid CCl 3 COHal (Hal = F, CI, Br, I). A linear correlation between the average 35 C1 NQR frequencies of the CC1 3 groups and the electronegativ-ities of the halogen atoms in the COHal groups has been discovered. The temperature-dependent NQR data reveal thermoactivated reorientations of the CCl 3 COHal molecules as a whole in the crystal lattice. The activation energies of this motion are found to lie in the range 31 -37 kJ mol 
  Reference    Z. Naturforsch. 51a, 751—754 (1996); received October 20 1995 
  Published    1996 
  Keywords    NQR spectroscopy, Molecular motion, Trichloroacetyl halides 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0751.pdf 
 Identifier    ZNA-1996-51a-0751 
 Volume    51 
4Author    A. Ramamoorthy, P. T. NarasimhanRequires cookie*
 Title    Numerical Design of Composite Pulses for Polycrystalline Samples in Pulsed NQR Spectroscopy  
 Abstract    The density matrix approach along with fictitious spin-1/2 or tensor operator formalisms were employed to obtain general expressions for </ x > and thus the signal induced in a coil in the case of physically equivalent non-interacting spin I = 1 and 3/2 nuclei in a single crystal with a three-pulse composite pulse. The corresponding powder averages were then obtained and the dependence of the signal on the i-th pulse flip angle (0,) and phase (0,) studied. A numerical procedure established the optimum "TT/2" composite pulse for polycrystalline samples as (90) o -(70) 45 -(20) 25 , where the quan-tity in parentheses denotes the flip angle and the subscript the phase. A two-pulse composite pulse of the form (126) 0 -(300) 80 was also inferred, but the three-pulse composite pulse is superior. These composite pulses are shown to have general validity for other spin I values. 
  Reference    Z. Naturforsch. 45a, 581—586 (1990); received August 24 1989 in revised form December 6 1989 
  Published    1990 
  Keywords    Composite pulses, NQR spectroscopy, Polycrystalline samples, Numerically designed pulses 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0581.pdf 
 Identifier    ZNA-1990-45a-0581 
 Volume    45