Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"superexchange"”.
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Exchange and superexchange interactions in quantum dot systems
… to utilize large quantum dots to mediate superexchange interaction and generate entanglement between distant spins. This opens up a possible mechanism for selectively coupling pairs of remote spins in a larger network of quantum dots. Taking advantage of this opportunity requires a deeper …
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ΚΒΑΝΤΟΧΗΜΙΚΗ ΚΑΙ ΠΕΙΡΑΜΑΤΙΚΗ ΜΕΛΕΤΗ ΤΗΣ ΔΟΜΗΣ ΚΑΙ ΤΩΝ ΦΑΙΝΟΜΕΝΩΝ ΥΠΕΡΑΝΤΑΛΛΑΓΗΣΔΙΚΕΝΤΡΙΚΩΝ D9:D9 ΜΑΓΝΗΤΙΚΩΝ ΣΥΣΤΗΜΑΤΩΝ ΜΕ ΓΕΦΥΡΕΣ ΕΚΤΕΤΑΜ...
… ON TWO OF THE COMPOUNDSREVEAL A WEAK SUPEREXCHANGE PHENOMENON TO BE PROPAGATED THROUGH THE BRIDGE. THE MAGNITUDE OF THE SUPEREXCHANGE SEEMS TO BE CONTROLLED BY THE LOCAL CHROMOPHORE GEOMETRY. THE EHMO, QUANTUM CHEMICAL RESULTS FOR MODEL COMPLEXES, ARE IN ACCORDANCE WITH THE ABOVE …
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Realizing quantum spin models with ⁷Li atoms in an optical lattice
… the energy of a second-order tunneling process (superexchange) maps to the parameters of a Heisenberg model. This thesis provides a detailed roadmap for the design and building of such a quantum simulator with ⁷Li atoms in optical lattices.
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Temperature dependent magnetic order in FeOCl type compounds
… chains by direct exchange, as well as by M-O-M superexchange. The different magnetic behaviors of MOCl are related to the different numbers of 3d electrons of M3+.
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Diluted Magnetic Semiconductor Nanomaterials Fabrication by a Chemical Vapor Deposition Method
… due to the antiferromagnetic coupling of direct superexchange interaction between Mn2+. The well-aligned DMS 1-dimensional Mn doped ZnO nanostructures have great potential for application in spintronic nanodevices.</p>
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Elektronentransferprozesse in gemischtvalenten Systemen, Redoxkaskaden und Polymeren auf Basis von Triarylaminredoxzentren
… z.B. bei 5+, der Elektronentransfer nach einem Superexchange-Mechanismus erfolgt. Bei der Verwendung einer elektronenreichen Dimethoxy-substituierten Brücke wie in 10+ kann der Elektronentransfer neben dem Superexchange- auch nach einem Hopping-Mechanismus erfolgen. Bei Verbindungen, die einen …
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Electrolyte Effects on the Kinetics of Comproportionation Electron-Transfer Reactions and on Intervalence Charge-Transfer Band Energies of Binuclear Ruthenium Ammine Complexes
… indicate an important role for hole-transfer superexchange in the ET transition state. The hypothesis of a catalytic ternary association complex, [RuII--X--RuIII] has also been explored by kinetic modeling of the reaction. An increasing ratio of anion-catalyzed k<sub>etx</sub> to uncatalyzed …
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Mechanistic Studies of Bimolecular Electron Transfer Self-Exchange Rates of Ruthenium Ammine Pyridyl Complexes Measured by NMR Line Broadening Techniques
… >Os > Ru. This could be explained as a probable “superexchange” type mechanism dominated by the “hole-transfer” pathway based on the trend between the catalytic effect and the redox potential of the particular M(CN)<sup>4-</sup> ion. Kinetic modeling data also show the strongest catalytic effect …
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Unusual Electron Transfer Rate Effects due to Pyridyl Ring Substituents and Trace Group VIII b Hexacyano Complexes as Added Salts
… NMR work (Yinshin,Q.;2011) we found that the superexchange ET catalysis by trace M<sup>II</sup>(CN)<sub>6</sub><sup>-4</sup> varied strongly in the order Ru < Os < Fe</p>
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Controlling ultracold fermions under a quantum gas microscope
… that doublon-hole bunching resulting from the superexchange excitations dominates and causes the charges to bunch. In order to increase the simulation capabilities, we updated the microscope with arbitrary optical potential imprinting ability. Using a digital micromirror device (DMD), a 2D box …
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Interfacial and long-range electron transfer at the mineral-microbe interface
… tunneling. These mechanisms suggest a superexchange electron transfer mechanism for OmcA and a redox-specific (i.e. heme-mediated) electron transfer mechanism for MtrC at mineral surfaces during bacterial metal reduction. Additionally, a novel electrochemical STM configuration was …
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Quantum gas microscopy of strongly correlated fermions
… and doublon-holon bunching, which arises from superexchange and is strongest at half-filling. The anti-bunching correlations at low filling can be interpreted as the first direct real-space observation of the interaction-enhanced Pauli hole.
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Effects of particles’ size and composition on magnetic properties of substituted ferrite nanoparticles
… a single-line signal indicative of dominant superexchange interactions. A small peak at very low magnetic field (about -500 ≤ H ≤ 500 G) was observed for the Zn- based oxide annealed at 1000 ◦C. This anomalous peak may be due to the low field microwave absorption(LFMA) phenomenon that is not …
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Spin Dynamics in a Tunable Heisenberg Magnet Realized with Ultracold Atoms
… effect: an effective magnetic field created by superexchange, which has its origin in the mapping from the Hubbard model and which has not been observed before. Bethe phantom states — excited many-body eigenstates of the Heisenberg model: For a given anisotropy, there exists one special winding …
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Optical and core-level X-ray spectroscopy of correlated two-dimensional materials
… gap in a process analogous to ground state superexchange. These results establish the microscopic origin of these excitons and provide a mechanism to explain their possible coupling to the magnetic order/excitations. Finally, we study the iron-based superconductor FeSe, which displays a …
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Single molecule optical absorption at room temperature detected by scanning tunneling microscopy
… dendron can be rationalized by a simple Förster/superexchange model. Simulations and scanning tunneling microscopy of single dendron molecules show that the dyes can fold over onto the dendron, creating a heterogeneous distribution of conformations suitable for single molecule studies of light …
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Electron transfer processes between organic redox centres and electrodes via active bridges in self-assembled monolayers
… Längenabhängigkeit des ETs als bei eine Superexchange-Mechanismus zu erwarten ist.
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Molecular-based magnets constructed from cyanometalate building blocks
… magnetization of 8.4 x 103 Gauss cm3 mol'1. A superexchange mechanism is presented which qualitatively accounts for the relative magnitude of the TN'S. The magnetic ordering temperature of CsMnn[Mnin(CN)6],1/2H20 is about 40 % lower than expected; this is attributed to the effects of cyanide …
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Redox properties of Bis-Triarylamines and ligand properties of Thianthrenophane
… it was inferred that the HT proceeds via superexchange mechanism. The analysis reveals that even significantly longer conjugated bridges should still mediate significant electronic interactions, because the decay constant of a series of conjugated MV species is small. The absorption …
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Modeling of mechanisms affecting the growth and breakdown of iron sulfide films
… order imposed by strong antiferromagnetic superexchange interactions that exist in pyrrhotite, which is a finding that is also important for other scientifically important material systems like NiO. The next section of the thesis discusses the mechanistic pathways and kinetic parameters of …