Sökning: "density functional"

Visar resultat 41 - 45 av 960 avhandlingar innehållade orden density functional.

  1. 41. A new generation density functional towards chemical accuracy

    Författare :Zhang Ying; Luo Yi; Head-Gordon Martin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bioengineering; Bioteknik;

    Sammanfattning : Density functional theory (DFT) has become the leading method in calculating theelectronic structures and properties from first principles. In practical applicationsof DFT in the frame work of Kohn-Sham (KS) method, an approximate exchange-correlation functional has to be chosen. LÄS MER

  3. 42. Computational Insights on Functional Materials for Clean Energy Storage : Modeling, Structure and Thermodynamics

    Författare :Tanveer Hussain; Rajeev Ahuja; Caetano R. Miranda; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Molecular dynamics; Hydrogen storage; Chemisorption; Physisorption; Functionalization; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The exponential increase in the demands of world’s energy and the devastating effects of current fossil fuels based sources has forced us to reduce our dependence on the current sources as well as finding cleaner, cheaper and renewable alternates. Being abundant, efficient and renewable, hydrogen can be opted as the best possible replacement of the diminishing and harmful fossil fuels. LÄS MER

  4. 43. Ab initio Lattice Dynamics : Hydrogen-dense and Other Materials

    Författare :Duck Young Kim; Rajeev Ahuja; Richard Needs; Uppsala universitet; []
    Nyckelord :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; Physics; Fysik;

    Sammanfattning : 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. LÄS MER

  5. 44. Oxygen Storage Chemistry of Nanoceria

    Författare :Dou Du; Kersti Hermansson; Peter Broqvist; Pavlin D. Mitev; Joachim Paier; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoceria; Density Functional Theory; Hybrid Functional; Oxygen Storage Capacity.; Kemi med inriktning mot materialkemi; Chemistry with specialization in Materials Chemistry;

    Sammanfattning : The versatile redox chemistry of ceria (CeO2) originates from its Ce4f electron, which plays the key role in changing the oxidation state of Ce between +IV and +III. Ceria is, among other things, a material that can act as a powerful oxygen buffer with a high oxygen storage capacity (OSC). LÄS MER

  7. 45. First Principles Studies of Functional Materials Based on Graphene and Organometallics

    Författare :Sumanta Bhandary; Biplab Sanyal; Olle Eriksson; Stefano Sanvito; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Graphene; Magnetism; Organometallics; Density functional theory; Electron correlation; Spin switching; Nanoribbons; Exchange interaction; Edge functionalization; Band gap; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : Graphene is foreseen to be the basis of future electronics owing to its ultra thin structure, extremely high charge carrier mobility,  high thermal conductivity etc., which are expected to overcome the size limitation and heat dissipation problem in silicon based transistors. LÄS MER