Search results for "Mixed−Valence Compounds"

showing 2 items of 2 documents

High‐nuclearity mixed‐valence magnetic clusters : A general solution of the double exchange problem

1996

We report here a general solution of the double‐exchange problem in the high‐nuclearity mixed valence systems containing arbitrary number P of the electrons delocalized over the network of N (P<N) localized spins. The developed approach is based on the successive (chainlike) spin‐coupling scheme and takes full advantage from the quantum angular momentum theory. In the framework of this approach the closed‐form analytical expressions are deduced for the matrix elements of the double exchange interaction, two‐electron transfer, and three‐center interaction that can be referred to as the potential exchange transfer. For the arbitrary nuclearity mixed‐valence systems the matrix elements of all …

Angular momentumValence (chemistry)SpinsChemistryExchange interactionExchange InteractionsGeneral Physics and AstronomyElectron TransferQuantum numberLocalized StatesUNESCO::FÍSICA::Química físicaDelocalized electronMolecular ClustersQuantum mechanicsMixed−Valence CompoundsPhysical and Theoretical ChemistryMatrix ElementsSpin−Lattice Relaxation:FÍSICA::Química física [UNESCO]Exchange Interactions ; Molecular Clusters ; Matrix Elements ; Electron Transfer ; Localized States ; Spin−Lattice Relaxation ; Mixed−Valence CompoundsQuantumBasis set
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Mixed‐valence trinuclear manganese clusters : Influence of the electronic transfer on the magnetic properties

1990

The magnetic behavior of mixed‐valence trinuclear clusters d4‐d4‐d5 is discussed on the basis of a model which takes into account valence delocalization and Heisenberg exchange. This model considers the competing effect between the electronic transfer and the localization of the extra electron due to an asymmetry of the triangular entity. The magnetic properties of the mixed‐valence oxo‐centered Mn(II)‐Mn(III)‐Mn(III) complexes formulated as Mn3O(O2CR)6L3 (R=Me, L=pyridine) are discussed on the basis of the developed model, supporting a significant intramolecular electron transfer. A comparison of these results to those previously reported by assuming a valence‐trapped model is given. Carlo…

Valence (chemistry)ChemistryMagnetic Propertiesmedia_common.quotation_subjectUNESCO::FÍSICAExchange InteractionsGeneral Physics and Astronomychemistry.chemical_elementManganeseElectronElectron TransferManganese ComplexesAsymmetryElectron transferCrystallographyDelocalized electronchemistry.chemical_compound:FÍSICA [UNESCO]Intramolecular forcePyridineMixed−Valence CompoundsAtomic ClustersAtomic physicsMixed−Valence Compounds ; Electron Transfer ; Magnetic Properties ; Atomic Clusters ; Manganese Complexes ; Exchange Interactionsmedia_common
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