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'Molecular motion' in keywords Facet   Publication Year 1996  [X]
Facet   section ZfN Section A  [X]
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1Author    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 
2Author    T. Ueda, K. Shimizu, H. Ohki, T. OkudaRequires cookie*
 Title    C CP/MAS NMR Study of the Layered Compounds [C 6 H 5 CH 2 CH 2 NH3] 2 [CH 3 NH 3 ] fI _ 1 Pb n l3 n+1 (n = 1, 2)  
 Abstract    19, 1996 13 C CP/MAS NMR spectra were measured on the layered compounds [C 6 H 5 CH 2 CH 2 NH 3 ] 2 [CH 3 NH 3 ] n _ 1 Pb"I 3n + j (w = 1, 2). The linewidth of the resonance peak corresponding to the phenyl carbons changed with temperature. The maximum broadening took place at 363 K for both com-pounds. The activation energy £ a for the reorientation of the phenyl group was determined to be 25 kJ mol" 1 for n — 1 and 26 kJ mol" 1 for n = 2. The frequency factor t 0 was evaluated from the linewidth at 363 K. The value of the second moment, estimated from the maximum linewidth, was interpreted by assuming a 180° flip of the phenyl group around its two-fold axis. The similarity of the activation energies for the reorientation of the phenyl group suggested that the local structure and the molecular motion of the organic cations is little affected by the difference in the sub-structure of the inorganic layer in those compounds. 
  Reference    Z. Naturforsch. 51a, 910—914 (1996); received March 
  Published    1996 
  Keywords    13 C CP/MAS NMR, Molecular motion, Layered compounds Activation parameters, Local structure 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0910.pdf 
 Identifier    ZNA-1996-51a-0910 
 Volume    51