Sökning: "Density-Functional Theory DFT"
Visar resultat 1 - 5 av 281 avhandlingar innehållade orden Density-Functional Theory DFT.
1. Nonlocal Correlations in Density Functional Theory
Sammanfattning : In Density Functional Theory, the widely used local and semilocal approximations to the exchange-correlation energy, the local density approximation (LDA) and the generalized gradient approximations (GGAs), lack a physical description of truly nonlocal correlation effects, which are absolutely essential for a proper description of soft matter. A scheme is proposed that provides a basis for systematic improvements beyond LDA and GGA, including correlations at intermediate and long range, giving rise to bonds of pure van der Waals type as well as more intricate, intermediate-range correlation bonds. LÄS MER
2. Atomistic modelling of functional solid oxides for industrial applications : Density Functional Theory, hybrid functional and GW-based studies
Sammanfattning : In this Thesis a set of functional solid oxides for industrial applications have been addressed by first principles and thermodynamical modelling. More specificially, measurable quantities such as Gibbs free energy, geometry and electronic structure have been calculated and compared when possible with experimental data. LÄS MER
3. Van der Waals density-functional description of polymers and other sparse materials
Sammanfattning : Polymers are abundant in nature --- rubber, tar and latex have been known to mankind for thousands of years. Early in the 20th century, a systematic synthesis of polymers was developed, but the great potential of synthesized polymers was recognized first during World War II. LÄS MER
4. Quantum aspects of hydrogen in metals and oxides from density-functional calculations
Sammanfattning : Atomic hydrogen dissolved in a solid or adsorbed on a solid surfacedisplays many remarkable features, and is a subject ofgreat technological interest.An increased understanding of hydrogen/solid systems can supportthe development of areas as diverse asproton exchange membranes for fuel cells,heterogeneous catalysis, and growth of semiconductor devices. LÄS MER
5. Theoretical prediction of properties of atomistic systems : Density functional theory and machine learning
Sammanfattning : The prediction of ground state properties of atomistic systems is of vital importance in technological advances as well as in the physical sciences. Fundamentally, these predictions are based on a quantum-mechanical description of many-electron systems. LÄS MER
