Search results for "Mössbauer"

Klimt artwork: red-pigment material investigation by backscattering Fe-57 Mössbauer spectroscopy, SEM and p-XRF

2017

Material tests were performed on a rediscovered Klimt-artwork "Trompetender Putto". We performed studies on the red colored spots, mainly taken from non-restored parts. MIMOS II Fe-57 Mossbauer spectroscopy (novelty in art-pigment analysis) mainly reveals haematite and crystallized goethite in red colors. Electron microscopy can identify various layers of the original and overpainting of an artwork. The number of layers fluctuates between three and four chemically painted areas. The portable X-ray fluorescence analysis enables to reduce the pigment list to containing mercury (cinnabar), lead, zinc, iron and titanium. Infrared-light-irradiation visualizes the different age of the pigments.

Structural and magnetic properties of Fe2CoGa Heusler nanoparticles

2012

Abstract Fe2CoGa Heusler nanoparticles are synthesized by a chemical method. The structure and magnetic properties of Fe2CoGa Heusler nanoparticles are investigated by x-ray diffraction, extended x-ray absorption fine structure and Mössbauer spectroscopy. The crystal structure of Fe2CoGa nanoparticles is described by the X-type structure (prototype: Li2AgSb). Magnetic measurements reveal the presence of small Fe2CoGa nanoparticles and lower magnetic moments compared with the theoretically predicted values.

Mössbauer gamma-ray diffraction from the molecular crystal KCN

1980

Abstract Mossbauer gamma-ray diffraction was applied to separate the elastic and inelastic scattering intensities from the (200), (400) and (600) Bragg reflections of KCN. The energy resolution of our experiment was 60 neV. The Debye-Waller factor extracted from the elastic data and the thermal diffuse inelastic data both increase towards phase transition, theoretically a logarithmic singularity was predicted.

Pressure effect on superconductivity in FeSe0.5Te0.5

2016

Due to the simple layered structure, isostructural FeSe and FeSe0.5Te0.5 are clue compounds for understanding the principal mechanisms of superconductivity in the family of Fe-based superconductors. High-pressure magnetic, structural and Mossbauer studies have been performed on single-crystalline samples of superconducting FeSe0.5Te0.5 with Tc = 13.5 K. Susceptibility data have revealed a strong increase of Tc up to 19.5 K for pressures up to 1.3 GPa, followed by a plateau in the Tc(p) dependence up to 5.0 GPa. Further pressure increase leads to a disappearance of the superconducting state around 7.0 GPa. X-ray diffraction and Mossbauer studies explain this fact by a tetragonal-to-hexagonal…

The heterodinuclear iron(III) and copper(II) molecule Cu(salen)Fe(acac)2NO3 and its iron precursor Fe(acac)2NO3. Synthesis, magnetic susceptibility, …

1992

Abstract The synthesis, EPR, magnetic and Mossbauer properties of two iron(III) complexes are reported. The heterodinuclear iron(III)-copper(II) complex Cu(salen)Fe(acac)2NO3 is obtained as an adduct from the reaction of the two mononuclear moieties, the Cu(salen) molecule and the mononuclear iron(III) molecule Fe(acac)2NO3 acting as a precursor of the dinuclear unit. The latter molecule itself has been prepared by ligand substitution from the tris-acetylacetonate Fe(acac)3. The dinuclear complex is characterized by comparing the properties of the mono- and the dinuclear complex. Fe(acac)2NO3 is identified from its typical IR spectrum with the main nitrate vibrations at 1380, 1250 and 1010 …

Synthesis and spectroscopic characterization of organotin derivatives ofN-benzoylglycylglycine

1991

Di- and tri-organotin derivatives of N-benzoylglycylglycine (HBzGlyGly) were synthesized and characterized by infrared, 1H, 13C NMR and 119Sn Mossbauer spectroscopy. Diorganotin derivatives appear to be dimer distannoxanes ([R2SnBzGlyGly]2O)2 (R = CH3, n-C4H9, n-C8H17) with a ladder-type structure where tin atoms are five-coordinated and N-benzoylglycylglycine alternatively acts as a unidentate or bridging bidentate ligand through the carboxylate group. For triorganotin derivatives R3SnBzGlyGly (R= CH3, n-C4Hg) we propose a polymeric structure where N-benzoylglycylglycine bridges planar SnC3 units through the carboxylate group.

PREDICTION OF MOESSBAUER PARAMETERS IN A DOUGLAS–KROLL–HESS FRAMEWORK

2008

Dielectric relaxation models applied of the dynamics of myoglobin as determined by Mössbauer spectroscopy

1996

Abstract Protein specific modes of motions are found in myoglobin crystals above 180 K. In this contribution we show that this type of motions can be analyzed by a Davidson-Cole, a Cole-Cole or a Havriliak-Negami distribution in analogy to dielectric relaxation. However, the temperature dependence of the obtained parameters is quite unusual indicating a broadening of the distributions with temperature instead of motional narrowing. This can be understood from the picture of conformational substates if one assumes that more and more substates become accessible with increasing temperature. The result shows that the analogy between glass forming organic liquids and proteins should not be exagg…

Electric relaxation and Mn3+/Mn4+ charge transfer in Fe-doped Bi12MnO20–BiMn2O5 structural self-composite

2016

Fe-doped Bi12MnO20–BiMn2O5 ceramics was sintered at 1130 K for 6 h in ambient air. Two centro-symmetric phases formed thermodynamically stable self-composite material that was deduced from X-ray pattern analysis. The lattice parameters were a = 10.147(8) Å—for the cubic I23 Bi12MnO20 phase; and a = 7.545(4) Å, b = 8.538(1) Å, c = 5.758(3) Å—for the orthorhombic Pbam BiMn2O5 phase. The 57Fe Mössbauer spectrum, recorded at room temperature, has shown pure electronic quadrupolar split. The major doublets reflected the occurrence of Fe3+ ions distributed in two sites, i.e., octahedral Fe4+O6 and square pyramidal Fe3+O5, with preferential occupation of the pyramidal sites, that was consistent wi…

119Sn M�ssbauer studies of bis[cysteinato(1?)-S]- and bis[penicillaminato(1?)-S]-diorganotin(IV) species in the crystalline state and in frozen aqueo…

1988

The bonding and the configuration of the tin environment in the title compounds {R2Sn[SCH2CH(NH3+)COO−]2 and R2Sn[SC(CH3)2CH(NH3+)COO−]2, indicated in the following as R2Sn(cysH)2 and R2Sn(penH)2 respectively} has been investigated through the determination of the Mossbauer-Zeeman spectra of Ph2Sn(cysH)2 and Ph2Sn(penH)2 in the solid state, and through conventional Mossbauer spectroscopy of Me2Sn(penH)2 in the solid state as well as of Me2Sn(cysH)2 and Me2Sn(penH)2 in aqueous solution (frozen). The treatment of the data by the pointcharge model approach suggested the general occurrence of a tetrahedral C2SnS2 core. In aqueous Hepes buffer, a tertiary amino nitrogen atom has been observed to…