Sökning: "Density functional perturbation theory"

Visar resultat 1 - 5 av 17 avhandlingar innehållade orden Density functional perturbation theory.

  1. 1. Gradient Corrections to Exchange Energies within Density Functional Theory

    Detta är en avhandling från Per-Sverre Svendsen, Dept. of Theoretical Physics, Solvegata 14 A, 22362 LUND

    Författare :Per-Sverre Svendsen; [1996]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; thermodynamics; statistical physics; exchange energy; Density functional theory; gradient corrections; classical mechanics; Mathematical and general theoretical physics; response theory.; quantum mechanics; gravitation; relativity; Matematisk och allmän teoretisk fysik; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Fysicumarkivet A:1996:Svendsen;

    Sammanfattning : The small-wavector expansions for the first- and second-order exchange energy kernels (second-and third-order functional density derivatives of the exchange energy) have been investigated. Expansion coefficients are found, both in the case of a statically screened Coulomb interaction and a 'bare' interaction. LÄS MER

  2. 2. Ab initio Lattice Dynamics Hydrogen-dense and Other Materials

    Detta är en avhandling från Uppsala : Universitetsbiblioteket

    Författare :Duck Young Kim; Uppsala universitet.; [2009]
    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; NATURAL SCIENCES Physics; NATURVETENSKAP 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

  3. 3. Time-Dependent Many-Body Perturbation Theory: Possibilities and Limitations

    Detta är en avhandling från Uppsala : Universitetsbiblioteket

    Författare :Marc Puig von Friesen; Lunds universitet.; Lund University.; Lunds universitet.; Lund University.; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Many-body perturbation theory; Correlation functions; Hubbard model; Non-equilibrium Green s functions; Fysicumarkivet A:2011:Puig von Friesen;

    Sammanfattning : Popular Abstract in Swedish Ett av de mest subtila begrepp i fysik är ``{\bf växelverkan}". I en alldaglig mening betyder växelverkan att skilda entiteter (som elektroner, människor eller galaxer) påverkar\footnote {I fysiken motsvaras denna påverkan av en kraft.} varandra. LÄS MER

  4. 4. Dynamics and Fluctuations in Single-Electron Tunneling Devices

    Detta är en avhandling från ; Chalmers tekniska högskola; Gothenburg

    Författare :Niklas Dittmann; [2018]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; quantum dot; time-dependent density-functional theory; perturbation theory; single-electron source;

    Sammanfattning : In recent years, it has been routinely achieved to build nanoscale electronic devices, which generate current pulses carrying only a single elementary charge. Realizations of these single-electron emitters are based on time-dependently driven quantum dots, on single-electron turnstiles built from superconductor/normal-metal hybrid structures, and also on nanosystems employing Lorentzian voltage pulses or surface acoustic waves. LÄS MER

  5. 5. Application and development of quantum chemical methods. Density functional theory and valence bond theory

    Detta är en avhandling från Stockholm : US-AB

    Författare :Fuming Ying; KTH.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES Chemistry Theoretical chemistry; NATURVETENSKAP Kemi Teoretisk kemi;

    Sammanfattning : This thesis deals with two disjoint subdiciplines of quantum chemistry.  One isthe most used electronic structure method today, density functional theory(DFT), and the other one of the least used electronic structure methods,valence bond theory (VB). LÄS MER