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'Jahn Teller Effect' in keywords
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1Author    Hiiseyin Kalkan, Ismet SenelRequires cookie*
 Title    Electron Paramagnetic Resonance Study of Cu 2+ in CdCa (CH 3 COO) 4 * 6H 2 0 Single Crystal  
 Abstract    The Electron Paramagnetic Resonance spectra of Cu 2+ in CdCa (CH 3 COO) 4 • 6H 2 0 (cadmium cal-cium tetraacetate hexahydrate) powder and single crystal have been recorded at 300 and 133 K. The angular variation of the spectra indicated the substitution of the host Cd 2+ with Cu 2+ . The observed val-ues of the g and A hyperfine tensors were found to be temperature dependent, and this dependence is discussed and explained on the basis of dynamic Jahn-Teller effects. The spin-Hamiltonian parameters were found to be axial symmetric at room temperature, whereas they showed deviations from axial sym-metry at low temperature. The g and A tensors where found to be coaxial within the limits of experi-mental errors, and the ground state wave functions of the complex at 300 and 133 K have been con-structed. 
  Reference    Z. Naturforsch. 55a, 729—732 (2000); received April 4 2000 
  Published    2000 
  Keywords    EPR, Crystal and Ligand Field, Jahn-Teller Effects 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0729.pdf 
 Identifier    ZNA-2000-55a-0729 
 Volume    55 
2Author    C. Friebel, V. Propach, D. ReinenRequires cookie*
 Title    in Mischkristallen BaXu^Zn^yFg Cu 2+ in Tetragonally Compressed Octahedral Coordination - Spectroscopic Investigations of Mixed Crystals Ba2Cii^.Zn1_xF6  
 Abstract    Usually the Jahn-Teller effect of Cu 2+ in a regular octahedral host lattice site leads to a tetragonal elongation with a small o-rhombic component. If the relevant crystallographic site is slightly tetragonally compressed however in the host lattice structure already — as in Ba 2 ZnF6 -the Jahn-Teller effect may stabilize this distortion symmetry as well. This can be deduced from the EPR-spectroscopic g M -values of 1.99 for the mixed crystals Ba^Zni.^Cu^Fg up to x = 0.3. The angular overlap parameters obtained from the ligand field spectra suggest in addition, that the tetragonal compression of the CuFß polyliedra is considerable, with CuF distances of about 1.90 A (2x) and 2.14 A (4x), respectively. Increasing cooperative elastic interactions between the CuFß polyhedia in the (001) planes at larger Cu 2+ -concentrations induce tetragonally elongated octahedra (with a small o-rhombic component) in antiferrodistortive order at x > 0.6. This cooperative Jahn-Teller order, which is characteristic for Ba2CuF6, can be verified simply by acentric displacements of the F~-ligands connecting two Cu 2+ -ions in the (001) planes. 
  Reference    (Z. Naturforsch. 31b, 1574—1584 [1976]; eingegangen am 13. August 1976) 
  Published    1976 
  Keywords    Jahn-Teller Effect, EPR Spectra, Ligand Field Spectra, Copper 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1574.pdf 
 Identifier    ZNB-1976-31b-1574 
 Volume    31 
3Author    H. Pausch, Hk, Müller-BuschbaumRequires cookie*
 Title    Zur Kristallstruktur von SrLaNi04 On the Crystal Structure of SrLaNi04  
 Abstract    Single crystals of SrLaNi04 were prepared with a new high temperature and high oxygen pressure method (C02-Laser radiation). The X-ray investigation shows, that this com-pound belongs to the K2NiF4-type (a — 381.3; c = 1268.7 pm; space group D^-14/mmm), with a stretched octahedral oxygen coordination around Ni 3+ . The octahedral distortion can only be explained by a geometrical effect. 
  Reference    Z. Naturforsch. 34b, 378—379 (1979); eingegangen am 20. November 1978 
  Published    1979 
  Keywords    Single Crystal, X-ray, Jahn-Teller Effect 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0378.pdf 
 Identifier    ZNB-1979-34b-0378 
 Volume    34 
4Author    Bernd Jakob, Dirk ReinenRequires cookie*
 Title    The Temperature-Variable Geometry of the Pseudo-Octahedral Cu06 Entity in Bis(methoxyacetato)diaquo-Copper(II) -a Single Crystal EPR Study  
 Abstract    The Cu —O bond lengths in the pseudooctahedral bis(methoxyacetato)diaquo-copper(II) com­ plex are determined by the Jahn-Teller effect on the one hand and by the bonding properties of the three different oxygen ligator atoms (from a carboxylate. water and ether group) on the other. It is derived from E PR single crystal and powder investigations between 4.2 and 350 K, that the system becomes fluxional above —120 K due to a continuous transition from a static to a (par­ tially) dynamic Jahn-Teller distortion. A model is presented, which allows to correlate the EPR results with the C u —O spacings, if they are calibrated with structural data at two different temperatures. The structure of the ground state potential surface of Cu2+ is derived from the spectroscopic data. 
  Reference    Z. Naturforsch. 42b, 1500—1506 (1987); received June 25 1987 
  Published    1987 
  Keywords    Jahn-Teller Effect, Fluxionality, E PR Spectra Copper(II) Complex 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-1500.pdf 
 Identifier    ZNB-1987-42b-1500 
 Volume    42