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Showing 1 to 20 of 49 for “"Jahn-Teller"”.
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Jahn-Teller distortions in layered nickel oxides
This thesis presents the results of my work on Jahn-Teller distorted transition metal oxides. The Jahn-Teller distortion is a key factor in important phenomena and applications of materials with octahedrally-coordinated transition metal ions such as batteries, high-temperature cuprate …
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An investigation by electron paramagnetic resonance of the Jahn-Teller effect in LiNbO₃¿:Cu²+
… most closely case 2), the so-called intermediate JahnTeller effect. High frequency EPR spectra must be obtained before Hamiltonians 3) and 4) can be entirely rulled out. Particular attention is given to the theoretical predictions of Hamiltonian 1) (the dynamic Jahn-Teller effective Hamiltonian) …
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Thermisches Verhalten von CuOn-Polyedern in ausgewählten Verbindungen: Wechselspiel zwischen lokaler Strukturverzerrung und Kristalltopologie
… in den untersuchten Verbindungen beruhen auf dem Jahn-Teller-Effekt. Cu-O-Tetraeder werden abgeflacht, Cu-O-Oktaeder gestreckt. Je nach Strukturtyp teilt sich die lokale Polyederverzerrung auch makroskopisch dem Gesamtkristall mit und führt zu einer Erniedrigung der Gesamtsymmetrie (Spinell, …
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Theoretical studies of structural and electronic properties in transition metal oxides
… earth ion size on the stability of the coherent Jahn-Teller distortions in undoped perovskite manganites, and symmetry-mode-based classical and quantum mechanical formalism of lattice dynamics. The formula based on tight-binding approach for the calculation of K-edge resonant inelastic x-ray …
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Magnetism, Structure and their Interactions
… electronic reason of this distortion is the band Jahn-Teller effect where the Jahn-Teller active states are 4d states of Rh which is accidently put at the Fermi level by spin splitting. Then, magnetic moment behavior under pressure in itinerant compounds is investigated in four cubic Laves phase …
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Crystal field aspects of the vibrational spectra of some metal complexes of tropolone and nitrogen donor ligands
… has been made of the effects of spin state and Jahn-Teller distortion on the vibrational spectra of the metal tropolonates. Of particular interest is the octahedral divalent metal tropolonate adducts, where the distortion of the copper complex is small, and the metal 2-thiotroponates where the …
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Investigating anharmonic effects in condensed matter systems
… and experiment -- the former predict a static Jahn-Teller distortion, whilst the latter leads to a dynamic Jahn-Teller effect. By including anharmonic corrections to the energy and nuclear wavefunction, we show that the inclusion of these effects results in agreement between first-principles …
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High-accuracy electronic structure quantum Monte Carlo for molecular systems
… between the aromaticity and second order Jahn-Teller effects. We have found that the dominant mechanism at small and intermediate sizes, which stabilizes the bond angle and bond length alternated geometries, is the secondorder Jahn-Teller effect while the aromatic isomer is always found to …
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Modeling the chemical and photophysical properties of gold complexes.
… in the optimized triplet exciton displays a Jahn-Teller distortion, and the Au---Au distance is reduced versus the ground state distance (i.e., two reasons for large Stokes' shifts).
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Synthese und Strukturen verschiedener neuer Galliumsilyle und eines Hexagallans mit Hilfe maßgeschneiderter Silanide
… zeigt für den Hexagallan-Cluster eine Jahn-Teller-verzerrte oktaedrische Struktur auf. Mit nur sechs Gerüstelektronenpaaren wäre nach dem Wade-Mingos-Konzept auch ein überkappter trigonal-bipyramidaler Cluster zu erwarten gewesen. Weiterhin konnte das Galloxan [Ga{Si(SiMe3)2Me}O]6 das …
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An analysis of the photoelectron and Rydberg states of formaldehyde /|nby Carol R. Lessard. -- 260 St. Catharines [Ont.] : Dept. of Chemistry, Brock University,
… with and perturb each other through pseudo-Jahn-Teller vibronic coupling. The vacuum ultraviolet spectrum contains a number of features which are difficult to explain, and two unusually sharp bands can only be identified as representing some form of electron promotion in formaldehyde.
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Engineering Band Structures in Correlated Oxides
… The temperature dependence of the derived Mn Jahn-Teller/Mott gap in large period superlattices is completely different from the small period, suggesting different spin ordering states reside in them. The electronic structure of two parent materials are coherently blended at the interface, and …
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Density Functional Studies of the Structure, Properties and Applications of Copper and Iron Complexes of 3,7-Diazabicyclo[3.3.1]nonane Derivatives
… bei den Kupfer(II) Komplexen verschiedene “Jahn-Teller-Isomere” isoliert werden. Die relativen Energien der Kupfer(I)-Verbindungen mit unterschiedlichen Geometrien erweisen sich als abhängig von der Substituendenposition am Pyridinring (ortho oder meta) und/oder der Größe des …
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Local Structures of Niobium-Containing Cation-Disordered Rocksalt Materials: Cobalt-Free Cathodes for Lithium-Ion Batteries
… combined with the accommodation of Mn Jahn-Teller and Nb second order Jahn-Teller distortions within the material. This cation ordering is found to be highly sensitive to the synthesis conditions and to have significant implications for the electrochemical performance of the material. …
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Vibrational and anion photoelectron spectroscopy of transition metal clusters
… (triangular and linear) and hints at pseudo Jahn-Teller and Jahn-Teller effects. Some of the PADs reveal an oscillatory energetic dependence that, according to the quantum analogy established by Fano with the Young’s double slit experiment, is interpreted as interferometric effects in the …
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Study of colossal magnetoresistance and pressure effects in La2/3Ca1/3MnO2 thin films /
… The double exchange mechanism (DE) and the Jahn-Teller deformations play an important role in CMR effect. Applied pressure has a very similar effect as does an applied magnetic field, except, at low temperatures (T<Tc) the field suppresses the resistivity more than pressure. In our study we …
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Luminescence of impurity-activated alkali halides under high pressure
… to display a doublet structure, due to both Jahn-Teller interactions and intermediate spin-orbit coupling. The effect of pressure on the room temperature emission is to cause a redistribution of intensity between the peaks of the doublet, with higher pressure favoring the higher energy A.r …
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Probing spin, charge and lattice coupling in manganites
… at higher pressures is found to result from the Jahn-Teller distortions of the MnO_6 octahedra and the localization of 3d electrons. The general trend is expected to be a characteristic feature of Colossal Magnetoresistance manganites.
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An ultrasonic study of point defects in electron-irradiated P-type silicon
… interstitial site and the surrounding lattice is Jahn-Teller distorted with e-type (tetragonal or <100> orthorhombic) symmetry.
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