Sökning: "Ab initio"

Visar resultat 11 - 15 av 251 avhandlingar innehållade orden Ab initio.

  1. 11. Ab initio simulations of core level spectra Towards an atomistic understanding of the dye-sensitized solar cell

    Detta är en avhandling från Stockholm : Department of Physics, Stockholm University

    Författare :Ida Josefsson; Stockholms universitet.; [2013]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiconfigurational quantum chemistry; CASSCF calculations; core-level spectroscopy; x-ray photoelectron spectroscopy; x-ray absorption; resonant x-ray scattering; dye solar cells; transition metals; kemisk fysik; Chemical Physics;

    Sammanfattning : The main focus of this thesis is ab initio modeling of core level spectra with a high-level quantum chemical description both of the chemical interactions and of local atomic multiplet effects. In particular, the combination of calculations and synchrotron-based core-level spectroscopy aims at understanding the local structure of the electronic valence in transition metal complexes, and the details of the solvation mechanisms of electrolyte solutions, systems relevant for the dye-sensitized solar cell. LÄS MER

  2. 12. Theoretical and Experimental Studies of Electrode and Electrolyte Processes in Industrial Electrosynthesis

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Rasmus Karlsson; KTH.; [2015]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Electrocatalysis; metallic oxides; ruthenium dioxide; titanium dioxide; DSA; doping; selectivity; ab initio modeling; density functional theory; Elektrokatalys; metalloxider; ruteniumdioxid; titandioxid; DSA; dopning; selektivitet; ab initio-modellering; täthetsfunktionalteori; Chemical Engineering; Kemiteknik;

    Sammanfattning : Heterogeneous electrocatalysis is the usage of solid materials to decrease the amount of energy needed to produce chemicals using electricity. It is of core importance for modern life, as it enables production of chemicals, such as chlorine gas and sodium chlorate, needed for e.g. materials and pharmaceuticals production. LÄS MER

  3. 13. New Electrolyte Materials for Lithium Batteries and Fuel Cells - an ab initio and vibrational spectroscopy study

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Henrik Markusson; [2006]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; IR spectroscopy; lithium salts; Raman spectroscopy; ab initio calculations; electron structure calculations; protic ionic liquids; electrolytes;

    Sammanfattning : In order to reduce our fossil based energy consumption there is an urge for new energy storage and conversion devices such as lithium batteries and fuel cells for more efficient energy use. The heart of these devices is an ion conducting electrolyte which needs to provide high performance at low cost. LÄS MER

  4. 14. Ab initio Interlayer Potentials For Metals and Alloys

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Fuyang Tian; KTH.; [2012]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mobius inversion; Potentials; EMTO; Järnvägsgruppen - Effektiva tågsystem för godstrafik; Järnvägsgruppen - Effektiva tågsystem för godstrafik; Järnvägsgruppen - Effektiva tågsystem för persontrafik; Järnvägsgruppen - Effektiva tågsystem för persontrafik;

    Sammanfattning : Many modern materials and material systems are layered. The properties related to layers are connected to interactions between atomic layers. In the present thesis, we introduce the interlayer potential (ILP), a novel model potential which fully describes the interaction between layers. LÄS MER

  5. 15. Insights into Materials Properties from Ab Initio Theory Diffusion, Adsorption, Catalysis & Structure

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Andreas Blomqvist; Uppsala universitet.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Molecular dynamics; Diffusion; Catalysis; Adsorption; Random structure search; Hydrogen-storage materials; Phase-change materials; NATURAL SCIENCES Physics Condensed matter physics Defects and diffusion; NATURVETENSKAP Fysik Kondenserade materiens fysik Defekter och diffusion; NATURAL SCIENCES Physics Condensed matter physics Surfaces and interfaces; NATURVETENSKAP Fysik Kondenserade materiens fysik Ytor och mellanytor; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, density functional theory (DFT) calculations and DFT based ab initio molecular dynamics simulations have been employed in order to gain insights into materials properties like diffusion, adsorption, catalysis, and structure.In transition metals, absorbed hydrogen atoms self-trap due to localization of metal d-electrons. LÄS MER