Search for dissertations about: "correlation energy hartree-fock"

Found 5 swedish dissertations containing the words correlation energy hartree-fock.

  2. 1. Magnetism in Transition Metal Systems : Interplay between structure, dimensionality and electron correlation

    Author : Samara Keshavarz Hedayati; Yaroslav Kvashnin; Patrik Thunström; Olle Eriksson; Tamio Oguchi; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Abstract : In this thesis, an ab initio study of electronic structures and magnetic properties of transition metal systems has been presented, covering bulk, interface and surface geometries. Among them are Fe, Co, Ni, CaMnO3, Co2MnSi, a ferromagnetic Heusler alloy, as well as double-perovskites oxides such as Sr3(Fe1.25Ni0.75)O6 and Nd2NiMnO6. READ MORE

  4. 2. Computational Atomic Structures Toward Heavy Element Research

    Author : Sacha Schiffmann; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Atoms; electron correlation; relativity; Quantum mechanics; calculations; natural orbitals; isotope shifts; hyperfine structures; transition parameters; Landé g factor; Fysicumarkivet A:2021:Schiffmann;

    Abstract : We are interested in complex electronic structures of various atomic and ionics systems. We use an ab initioapproach, the multiconfigurational Dirac-Hartree-Fock (MCDHF), to compute atomic structures and properties. READ MORE

  5. 3. Bose-Einstein Condensation of Magnetic Excitons in Semiconductor Quantum Wells

    Author : Vitalie Boţan; Lars Nordström; Sveatoslav Moskalenko; Pavlos Lagoudakis; Uppsala universitet; []
    Keywords : Physics; Bose-Einstein condensation; magnetic excitons; electron-hole pairs; electron-hole liquid; magnetorotons; magnetoplasmons; superfluidity; Fysik;

    Abstract : In this thesis regimes of quantum degeneracy of electrons and holes in semiconductor quantum wells in a strong magnetic field are studied theoretically. The coherent pairing of electrons and holes results in the formation of Bose-Einstein condensate of magnetic excitons in a single-particle state with wave vector K. READ MORE

  6. 4. Numerical Renormalization, Doped Antiferromagnets, and Statistics - Topics in Low Dimensional Physics

    Author : Martin Andersson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Josephson junctions; matrix-product states; fictitious flux; phase-separation; renormalization; stripes; t-J model; anyons; DMRG;

    Abstract : The first part of the thesis deals with so called numerical renormalization group methods, and in particular the density-matrix renormalization group (DMRG). This method performs extremely well for large one-dimensional quantum systems like spin-chains and Hubbard models. READ MORE

  7. 5. X-ray spectroscopies through damped linear response theory

    Author : Thomas Fransson; Patrick Norman; Christoph Jacob; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In order to reach a fundamental understanding of interactions between electromagnetic radiation and molecular materials, experimental measurements need to be supplemented with theoretical models and simulations. With the use of this combination, it is possible to characterize materials in terms of, e.g. READ MORE