Sökning: "Density functional perturbation theory"

Visar resultat 6 - 10 av 20 avhandlingar innehållade orden Density functional perturbation theory.

1. 6. Surface Vibrational and Electron Spectroscopy - Experiments and first-principle calculations

   Författare :Martin Andersson; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gränsskikt; anharmonicity; Ytkemi; Surface and boundary layery chemistry; adsorbates; metal surface; density functional theory; first-principle calculations; electron spectroscopy; reflection-absorption infrared spectroscopy; vibrational spectroscpy;

   Sammanfattning : This work deals with interpretation of experimental surface spectroscopic data with the aid of first-principle calculations. Surface infrared reflection-absorption spectra as well as spectra from the electron spectroscopic methods photoemission and X-ray absorption are considered. LÄS MER

3. 7. On the defective origin of conductive and structural properties of oxides: insights from first principles

   Författare :Anders Lindman; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; point defects; thermodynamic modeling; proton conductors; oxyhydrides; density-functional theory; BaZrO3; polarons; grain boundaries; space charges; oxides;

   Sammanfattning : Oxides are versatile materials with applications in many different research fields; especially those related to clean energy technologies, such as fuel cells, batteries and solar panels. Many functional properties of these materials derive from lattice imperfections, or defects, and a lot of effort has been put into fine tuning these materials by modifying their structure on the atomic scale. LÄS MER

4. 8. Amorphous and crystalline functional materials from first principles

   Författare :Leyla Isaeva; Olle Eriksson; Jörg Neugebauer; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; first-principles theory; lattice dynamics; phase transitions; amorphous materials; tribology; ultrafast magnetism;

   Sammanfattning : This thesis deals with various functional materials from first-principles methods and is divided into two major parts according to the underlying atomic structure of the system under study. The first part of the thesis deals with the temperature-induced structural phase transitions in metallic  β'-AuZn and perovskite oxide LiOsO3. LÄS MER

5. 9. Correlated Electronic Structure of Materials : Development and Application of Dynamical Mean Field Theory

   Författare :Patrik Thunström; Olle Eriksson; Alexander Lichtenstein; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; DMFT; correlation; entanglement; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : This thesis is dedicated to the development, implementation and application of a combination of Density Functional Theory and Dynamical Mean Field Theory. The resulting program is shown through several examples to be a powerful and flexible tool for calculating the electronic structure of strongly correlated materials. LÄS MER

7. 10. Density Functionals for Dynamic Linear Response in Finite Systems

   Författare :Maria Hellgren; Matematisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This dissertation investigates a new method for obtaining excited-state properties of finite, many-electron systems such as atoms, molecules and nano-systems. The method combines the merits of many-body perturbation theory and time-dependent perturbation theory and yields approximate density response functions which preserve basic physical conservation laws. LÄS MER