Sökning: "density functional theory DFT"

Visar resultat 1 - 5 av 282 avhandlingar innehållade orden density functional theory DFT.

  1. 1. Nonlocal Correlations in Density Functional Theory

    Författare :Henrik Rydberg; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bonding; GGA; adhesion; graphene; DFT; exchange; adsorption; LDA; first principles; polarization; vdW; determinants; correlation; graphite; surface states; van der Waals; density-functional theory; physisorption; nonlocal; functional;

    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. 2. Atomistic modelling of functional solid oxides for industrial applications : Density Functional Theory, hybrid functional and GW-based studies

    Författare :Cecilia Århammar; Rajeev Ahuja; Steven Louie; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density functional theory; oxides; GW; Condensed matter physics; Kondenserade materiens fysik; Magnetism; Magnetism; Defects and diffusion; Defekter och diffusion;

    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. 3. Synchrotron Radiation Studies of Molecular Building Blocks for Functional Materials

    Författare :Teng Zhang; Carla Puglia; Nils Martensson; Svante Svensson; Valeria Lanzilotto; Albano Cossaro; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Synchrotron radiation study; Functional materials; Molecular building blocks; Electron donor; 2D material; Gas-phase; Organic thin film; Electronic structure; Molecule-molecule interaction; Molecule-substrate interaction; Photoelectron spectroscopy; PES; XPS; Near edge X-ray absorption fine structure; NEXAFS; X-ray Absorption Spectroscopy; XAS; Au 111 ; Cu 111 ; Surface; Interface; Electronic structure; H-bonding; Cobalt phthalocyanine; CoPc; Triphenylamine; TPA; DPTA; m-MTDATA; Melamine; Biphenylene; Carbon nitride; Graphenylene; Density functional theory; DFT; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The research on new materials is a primary driving force for progress in human society. One of the most significant research topic nowadays is the development of new functional materials for technological applications, like perovskite implemented in solar cells, and graphene as a representative for the new 2D materials family. LÄS MER

  4. 4. Density Functional Theory for EPR and NMR Spin Hamiltonian Parameters

    Författare :Zilvinas Rinkevicius; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DFT; EPR; NMR; response theory; Theoretical chemistry; Teoretisk kemi;

    Sammanfattning : .... LÄS MER

  5. 5. Van der Waals density-functional description of polymers and other sparse materials

    Författare :Jesper Kleis; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; softmatter; Density functional theory; polyethylene; van der Waals interaction; polymer crystal; nanotubes; DFT; sparse material systems; polymer interactions; polymer structure;

    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