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'Mössbauer effect' in keywords
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1996 (3)
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1Author    DesmondC. CookRequires cookie*
 Title    Measurement of Nuclear Quadrupole Interactions using Mössbauer Spectroscopy  
 Abstract    Mössbauer spectroscopy is a useful probe for investigating nuclear quadrupole interactions. It enables the magnitude, sign and asymmetry of the electric quadrupole coupling constant to be determined. It is especially important for its ability to measure these parameters for excited nuclear states. The Mössbauer effect is used to measure excited state quadrupole moments in materials whose electric field gradient (EFG) is known. More commonly however, it is used to determine the EFG from which atomic bonding and electronic structure are determined. The technique also allows temperature dependent orientation of sublattice magnetization to be measured using the direction of the electric quadrupole coupling as a reference. 
  Reference    Z. Naturforsch. 51a, 368—372 (1996); received November 20 1995 
  Published    1996 
  Keywords    Mössbauer Effect, Electric Field Gradient, Quadrupole Interaction 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0368.pdf 
 Identifier    ZNA-1996-51a-0368 
 Volume    51 
2Author    Koji Yamada, Takashi Matsui, Tomoko Tsuritani, Tsutomu Okuda, Sumio IchibaRequires cookie*
 Title    I-NQR, 119 Sn Mössbauer Effect, and Electrical Conductivity of MSnI 3 (M = K, NH 4 , Rb, Cs, and CH 3 NH 3 )  
 Abstract    In a series of MSnI 3 compounds (M = K, NH 4 , Rb, Cs, CH 3 NH 3) two types of coordination around the central Sn(II) were found by 127 I-NQR and powder X-ray diffraction techniques. They are square pyramidal (for M = NH 4 , Rb) and octahedral (for M = CH 3 NH 3). CsSnI 3 , on the other hand, showed a drastic structural change of the anion at 425 K from a square pyramid to a regular octahedron. Associated with this phase transition, the electrical conductivity increased from 4xlO~ 3 Scm _1 to about 10 2 S cm" 1 . This metallic modification was characterized by 127 I-NQR and 119 Sn Mössbauer spectroscopy. 
  Reference    Z. Naturforsch. 45a, 307—312 (1990); received August 24 1989 in revised form October 28 1989 
  Published    1990 
  Keywords    NQR, Mössbauer effect, Perovskite compound, Phase transition, Electrical conductivity 
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 TEI-XML for    default:Reihe_A/45/ZNA-1990-45a-0307.pdf 
 Identifier    ZNA-1990-45a-0307 
 Volume    45 
3Author    Michel Molinier, Christoph Frommen, Werner Massa, Jürgen Pebler, Thierry RoisnelRequires cookie*
 Title    Magnetism of Alkalitetrafluoromanganates (III) AM11F4 (A = K, Rb, Cs): Neutron Diffraction, Mössbauer and Magnetization Investigations  
 Abstract    The magnetic properties of the d 4 Jahn-Teller systems A'Mn m F 4 with layered structures were investigated. Neutron diffraction on powders of KMnF 4 and RbMnF 4 revealed different antiferro-magnetic spin arrangements below T N = 4.5 K and 2.3 K, respectively: for KMnF 4 canted antiparal-lel along a and b, for RbMnF 4 parallel along a and antiparallel along b, in both cases parallel along c, the stacking direction of layers. Mössbauer investigations on 57 Fe doped KMnF 4 confirmed a spin orientation approximately within the layer plane. A discussion is given of the contributions to the magnetic hyperfine field and the Mössbauer linewidth in quasi-two-dimensional antiferromagnets with Ising anisotropy due to thermal excitation of domain wall dynamics (solitons). The experimen-tal data seem to confirm the predicted exponential temperature dependence of the linewidth. From magnetization measurements on powders and a single crystal of KMnF 4 the 2-d exchange energy and the out-of-plane and in-plane anisotropies could be extracted. In addition, from susceptibility measurements the exchange energies of NaMnF 4 , RbMnF 4 and CsMnF 4 were calculated. A linear dependence of these exchange energies (positive for ferromagnetic CsMnF 4 , negative for the other AMnF 4 compounds) on the cos 2 of the Mn-F-Mn bridge angle is observed and compared with the behaviour of the AFeF 4 compounds which is also linear but with reverse sign of the slope. The specific superexchange mechanisms active in Jahn-Teller systems with antiferrodistortively ordered layers are suggested to be responsible for these findings. 
  Reference    Z. Naturforsch. 48a, 1054—1072 (1993); received September 17 1993 
  Published    1993 
  Keywords    Neutron diffraction, Mössbauer effect, Magnetization, Exchange and anisotropy energy 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-1054.pdf 
 Identifier    ZNA-1993-48a-1054 
 Volume    48 
4Author    A.N G ArgRequires cookie*
 Title    Correlation of Mössbauer Quadrupole Splitting ( zI/?q) and Infrared Cyanide Frequency Separation in Alkali Metal Ferricyanides  
 Abstract    Mössbauer and infrared spectra of the alkali metal ferricyanides M* [Fe(CN)6] • n H 20 , where M1 = H , Li and N a were studied at room temperature. All the three compounds displayed a doublet with small quadrupole splitting (AEq). Infrared spectra of these compounds in solid state gave two frequencies for C = N stretching vibrations with their separation (Av) in increasing order which was found to be linearly correlated with AEq. A plausible explanation has been given in terms of the interaction of Li+ and Na+ cations w ith the CN-ligands of octahedrally symmetric ferricyanide anion [Fe(CN)6] 3-similar to that of hydrogen atoms which are hydrogen bonded in H 3Fe(CN)6. 
  Reference    (Z. Naturforsch. 30b, 96—98 [1975]; received February 1 /September 3 1974) 
  Published    1975 
  Keywords    Mössbauer Effect, IR Spectra, Ferricyanide Complexes, Hydrogen Bonding, Molecular Structure 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0096.pdf 
 Identifier    ZNB-1975-30b-0096 
 Volume    30 
5Author    M. I. OshtrakhRequires cookie*
 Title    Mössbauer Effect in Biomedical Research: Variations of Quadrupole Splitting in Relation to the Qualitative Changes of Biomolecules  
 Abstract    This review deals with studies of the variations of quadrupole splitting, electronic structure and stereochemistry of iron associated with qualitative changes of biomolecules. The possibility to determine various iron containing species resulting from the destruction of biomolecules using Mössbauer parameters is shown. A small change of iron stereochemistry leads to a small change of the iron electronic structure which could be detected by small changes of quadrupole splitting. It is expected that quadrupole splitting of iron gives new information for biomedical research on a molecular level. 
  Reference    Z. Naturforsch. 51a, 381—388 (1996); received October 20 1995 
  Published    1996 
  Keywords    Mössbauer effect, Biomedical research, Quadrupole splitting, Iron electronic structure, Hemoglobin, Molecular diseases 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0381.pdf 
 Identifier    ZNA-1996-51a-0381 
 Volume    51 
6Author    Tetsuaki NishidaRequires cookie*
 Title    Verification of the " Tg-A Rule" in Potassium Silicate and Sodium Tungstate Glasses  
 Abstract    A linear relationship exists in oxide glasses between glass transition temperature (T g) and quadrupole splitting (A) of Fe ,+ . DTA and Mössbauer measurements of silicate and tungstate glasses yielded large slopes of 680 and 260 °C/(mm s~ 1) from the slope of the straight lines when Fe 3+ occupied, as network former (NWF), distorted tetrahedral Si 4+ and distorted octahedral W 6+ sites, respectively. This linear relationship, named a 'T g -Z\ rule", suggests that F e is in proportion to the distortion of NWF-oxygen polyhedra and a higher activation energy is required for the fragments of glass to have a cooperative movement in the supercooled liquid state. The rule" was also valid in the case of potassium silicate glasses heat treated at the temperature close to 7g, indicating a distortion of Si0 4 and Fe0 4 tetrahedra. Substitution of Fe 3+ for individual NWF in silicate and tungstate glasses was confirmed from the Fourier transform infrared (FT-IR) spectra because only the absorption bands due to Si and W were respectively observed without the bands due to Fe. 
  Reference    Z. Naturforsch. 51a, 620—626 (1996); received November 2 1995 
  Published    1996 
  Keywords    Mössbauer effect, silicate glass, tungstate glass, glass transition temperature, quadrupole splitting 'T g -_\ rule" 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0620.pdf 
 Identifier    ZNA-1996-51a-0620 
 Volume    51