ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Study of the environment of Fe3+ in Na2Cd(SO4)2 2H2O by EPR (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 82 (1985), S. 4358-4361 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An EPR experiment on Fe3+ in a single crystal of Na2Cd(SO4)2 2H2O was carried out at Q band frequency and nitrogen temperature. The angular dependencies of the spectra were studied in the three crystallographic planes. In order to have a very precise orientation of the crystal, the experiment was done with a twinned crystal (superposition of two spectra in all three planes). The zero-field splitting of Fe3+ is of the same order of magnitude as the quantum hν, so that many ΔM=2 transitions were observed. All spin-Hamiltonian parameters (20) were calculated using observed ΔM=1 and ΔM=2 transitions for 30 different orientations of the magnetic field. The pseudosymmetries of the fourth-order term of the spin Hamiltonian of Fe3+ are compared to those we calculated using the superposition model. It is seen that Fe3+ is substituted for Cd2+ and that the orientation of the ocatahedral environment of Fe3+ does not differ much in orientation from that of Cd2+. Differences between the distortions of the Cd–O6 and Fe–O6 octahedra are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.448976
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    EPR of Gd3+ in Na2Cd(SO4)22H2O, comparison with previous results obtained for Fe3+ (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 6088-6090 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An EPR experiment on Gd3+ in a single crystal of Na2Cd(SO4)22H2O (CdK) was carried out at Q band frequency and nitrogen temperature. Two spectra related by symmetry were observed. All spin Hamiltonian constants have been calculated. The pseudosymmetries of the fourth-order term of the spin Hamiltonian are compared to those of Fe3+. It is observed that the substitution of Gd3+ for Cd2+ induced a very important local distortion of the host lattice, which is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449599
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Local environment of Gd3+ in MgF2 (1990)
    Springer
    Physics and chemistry of minerals 17 (1990), S. 34-37 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The electron paramagnetic resonance (EPR) of Gd3+ in MgF2 reveals that Gd3+ has two different environments in the lattice. One of them has D 2h symmetry, the EPR spectrum is characterized by a large zero field splitting [B 2 0 = 968.10−4 cm−1; B 2 2 = 357.10−4 cm−1] and the fourth order term of the spin Hamiltonian is axial; it is assumed that one Gd3+ substitutes two Mg2+. The other Gd3+ center has only monoclinic symmetry. From the analysis of the fourth order term of the spin Hamiltonian of the corresponding spectrum it is seen that one Gd3+ substitutes one Mg2+ and that this substitution produces a large local distortion of the lattice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209223
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Study of the symmetry of Fe3+ sites in SnO2 by electron paramagnetic resonance (1988)
    Springer
    Physics and chemistry of minerals 15 (1988), S. 300-303 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Electron paramagnetic resonance (EPR) of Fe3+ in SnO2 has been realized in a natural single crystal of cassiterite at 9.55 GHz (X-band) and at 34.40 GHz (Q-band). Spectra show the simultaneous presence of four groups of independent signals, each one typical of the immediate environment of a specific paramagnetic iron. Fe3+ always substitutes Sn4+ in an octahedral site. The four paramagnetic centers are due to four different charge compensation mechanisms. The spin Hamiltonian constant values for the SN center and I1 center confirm the former results of the authors about for these two centers. SN and I1 present a weak deviation from axial symmetry. The first preserves the crystallographic local symmetry of the tin site and the second shows a symmetry deviation of 0.6° probably due to the presence of an OH group in the coordination polyhedron. On the other hand, for the Sd1 center and mostly for the Sd2 center, never previously subjected to single crystal EPR measurements, the study of spectra symmetry and the determination of B 2 0 and B 2 2 constants produced new data. The Sd1 center could be due to a relaxation of the lattice together with a non local charge compensation mechanism. The Sd2 center presents a strong deviation from axial symmetry with mm local symmetry coordination due to coupling of Fe3+ and Nb5+. This coupling is proven by EPR studies of synthetic cassiterites doped with iron and niobium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307520
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Local distortion of the spodumene structure around isolated cations using E.P.R. and the superposition model (1985)
    Springer
    Physics and chemistry of minerals 12 (1985), S. 145-148 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The superposition model is used to attempt to explain the EPR spectrum of Fe3+ in spodumene (LiAlSi2O6). Two different models for the distortion of the local environment of Fe3+ are considered. If the local structure around Fe3+ is distorted toward that of its isomorphic compound LiFeSi2O6, it is possible to obtain an agreement between experimental data and calculated constants, only if it is considered that the values of $$\bar B_2$$ are different for the two non equivalent oxygens O1 and O2. A second model of local distortion of the structure, based on crystal chemical considerations, is proposed. With this model, it is possible to explain the EPR spectrum with a single value of $$\bar B_2$$ . It is seen that the local arrangement around isolated Fe3+ in spodumene may be different from that in LiAlSi2O6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Pseudo-symmetries of crystallographic coordination polyhedra. Application to forsterite and comparison with some EPR results (1980)
    Springer
    Physics and chemistry of minerals 6 (1980), S. 9-17 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract A quantitative analysis of the distortion of octahedral and tetrahedral coordination polyhedra with respect to perfect symmetry in crystal structures is presented. The distortion of a polyhedron is defined by all the fourfold and threefold pseudo-symmetries. Tests on the significance of the pseudo-symmetries are presented. In forsterite the results are compared to ones previously proposed, based on the pseudo-symmetry of fourth order expansion of the crystal field, and also compared to the pseudo-symmetries of the environment of Mn2+ and Gd3+ that were determined by electron paramagnetic resonance (EPR) measurements. Agreements and differences between these results are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308389
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Characterization and origin of two Fe3+ EPR spectra in kaolinite (1993)
    Springer
    Physics and chemistry of minerals 20 (1993), S. 242-247 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The electron paramagnetic resonance (EPR) spectra of Fe3+ in a well cristallized kaolinite from Decazeville in France are well resolved. It is shown that in this sample there are mainly two slightly different spectra, well separated at low temperature and characterized at -150° C by the constants B 2 0 = 0.112 cm−1, B 2 2 = 0.0688 cm−1 for one and B 2 0 = 0.116 cm−1, B 2 2 = 0.0766 cm−1 for the second. These two spectra arise from Fe3+ substituted for Al3+ at the two octahedral positions in equal amounts. The temperature dependence of EPR spectra was studied and was explained by a modification of the octahedral sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Electron paramagnetic resonance and ENDOR studies of Cr3+ - Al3+ pairs in forsterite (1983)
    Springer
    Physics and chemistry of minerals 9 (1983), S. 95-101 
    Details
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The electron paramagnetic resonance (EPR) spectrum of Cr3+ in synthetic crystals of forsterite consists primarily of lines of Cr3+ “isolated” at the M1 and M2 positions in a “perfect” crystal environment without local charge compensation. In addition it shows two nonequivalent superhyperfine-split sextets with different intensities which are due to strong interaction of the Cr3+ electron spin S (S=3/2) with an adjacent nuclear spin I(I=5/2). Electron nuclear double resonance (ENDOR) experiments revealed that the sextets result from Cr3+ (M1) - Al3+ and Cr3+ (M2) - Al3+ pairs, Al being located at adjacent tetrahedral Si sites. The g, D, A, and A′ tensor components of the Cr3+ - Al3+ pairs have been determined at room temperature. The values of the pairs are distinct although they are not very different from the corresponding data of “isolated” Cr3+. From the intensities of the EPR spectra the relative concentration of the Cr3+ - Al3+ pairs with respect to “isolated” Cr3+ has been estimated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308364
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    facet.materialart.
    Unknown
    Electron paramagnetic resonance of Fe3+ in diopside and spodumene (1973)
    American Institute of Physics
    Details
    Publication Date: 1973-07-01
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Published by American Institute of Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Site Assignment of Fe3+in Low Symmetry Crystals. Application to NaAlSi3O8 (1972)
    American Institute of Physics
    Details
    Publication Date: 1972-06-01
    Print ISSN: 0021-9606
    Electronic ISSN: 1089-7690
    Topics: Chemistry and Pharmacology , Physics
    Published by American Institute of Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...