Search for dissertations about: "lattice dynamics"

Showing result 1 - 5 of 72 swedish dissertations containing the words lattice dynamics.

  1. 1. Ab initio Lattice Dynamics Hydrogen-dense and Other Materials

    University dissertation from Uppsala : Universitetsbiblioteket

    Author : Duck Young Kim; Uppsala universitet.; [2009]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Density functional perturbation theory; Hydrogen-dense materials; Phase transition; High pressure; Ab initio lattice dynamics; Superconductivity; Quasi-particle approximation; NATURAL SCIENCES Physics; NATURVETENSKAP Fysik;

    Abstract : This thesis presents a theoretical study of materials under high pressure using ab initio lattice dynamics based on density functional theory and density functional perturbation theory using both super-cell and linear response approach.Ab initio lattice dynamics using super-cell approach is applied to compare our theoretical predictions with experimental findings. READ MORE

  2. 2. Dynamics in Ceria and Related Materials from Molecular Dynamics and Lattice Dynamics

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Anders Gotte; Uppsala universitet.; [2006]
    Keywords : Inorganic chemistry; molecular dynamics; diffusion; surface dynamics; ionic surfaces; Oorganisk kemi;

    Abstract : In discussions of heterogeneous catalysis and other surface-related phenomena, the dynamical properties of the catalytic material are often neglected, even at elevated temperatures. An example is the three-way catalyst (TWC), used for treatment of exhaust gases from combustion engines operating at several hundred degrees Celsius. READ MORE

  3. 3. Electron-Lattice Dynamics in pi-Conjugated Systems

    University dissertation from Linköping : Linköping University Electronic Press

    Author : Magnus Hultell (Andersson); Linköpings universitet.; Linköpings universitet.; [2007]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Polaron dynamics; Exciton dynamics; pi-conjugated systems; Su-Schrieffer-Heeger SSH model; Adiabaticity; Charge carrier transport; Organic electronics.; NATURAL SCIENCES Physics Other physics Computational physics; NATURVETENSKAP Fysik Övrig fysik Beräkningsfysik;

    Abstract : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. READ MORE

  4. 4. Electronic Structure and Lattice Dynamics of Elements and Compounds

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Petros Souvatzis; Uppsala universitet.; [2007]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; electronic structure; lattice dynamics; first-principles theory; self-consistent lattice dynamical calculation; elasticity; super plasticity; electronic topological transition; equation of state; Atom- och molekylfysik;

    Abstract : The elastic constants of Mg(1-x)AlxB2 have been calculated in the regime 0<x<0.25. The calculations show that the ratio, B/G, between the bulk- and the shear-modulus stays well below the empirical ductility limit, 1. READ MORE

  5. 5. Electron-lattice dynamics in π-conjugated systems

    University dissertation from Linköping : Linköping University Electronic Press

    Author : Magnus Hultell (Andersson); Linköpings universitet.; Linköpings universitet.; [2008]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; charge transport; electron-lattice dynamics; polaron; adiabatic transport; electron localization; internal conversion; NATURAL SCIENCES Physics Other physics Computational physics; NATURVETENSKAP Fysik Övrig fysik Beräkningsfysik;

    Abstract : The work presented in this thesis concerns the dynamics in π-conjugated hydrocarbon systems. Due to the molecular bonding structure of these systems there exists a coupling between the electronic system and the phonons of the lattice. READ MORE