Search for dissertations about: "non-local correlation"

Showing result 1 - 5 of 11 swedish dissertations containing the words non-local correlation.

  2. 1. Theory of van der Waals bonding: from bulk materials to biomolecules

    Author : Elisa Londero; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; alkanes; extended systems; DNA; band structure; van der Waals Density Functional vdW-DF ; exchange functionals; Density Functional Theory; non-local correlation; layered oxides;

    Abstract : Sparse matter is abundant in Nature.It encompasses systems characterized by an intrinsic low density of electrons in sizeable regions, where the van der Waals forces contribute considerably to cohesion.Given the length scale of the problem, a prediction of these materials requires appropriate tools within a quantum-mechanical framework. READ MORE

  4. 2. Van der Waals Interactions in Density Functional Theory

    Author : Erika Hult; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; van der Waals interaction; exchange-correlation energy; adhesion; intermolecular forces; physisorption; density functional theory;

    Abstract : Density functional theory is a very important method for calculating ground-state properties for atoms, molecules and solids. Albeit exact in principle, its implementation requires an approximation for the so-called exchange-correlation energy. READ MORE

  5. 3. A new generation density functional towards chemical accuracy

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

    Abstract : 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. READ MORE

  6. 4. Distorted Space and Multipoles in Electronic Structure Calculations

    Author : Fredrik Bultmark; Lars Nordström; Susanne Mirbt; Olle Eriksson; Sergej Savrasov; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; materials science; condensed matter theory; density functional theory; Magnetism; Atomic and molecular physics; Atom- och molekylfysik;

    Abstract : This thesis concerns methods for electronic structure calculations and some applications of the methods. The augmented planewave (APW) basis set and it’s relatives LAPW (linearised APW) and APW+lo (local orbitals) have been widely used for electronic structure calculations. READ MORE

  7. 5. Analytical and Numerical Developments in Strongly Correlated Systems: Perspectives from TDDFT and Green's Functions

    Author : Daniel Karlsson; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Many-Body Perturbation Theory; Hubbard model; TDDFT; Green s function; DFT; Quantum Transport; Disorder; Fysicumarkivet A:2014:Karlsson;

    Abstract : This thesis investigates different methods for treating strongly correlated systems, and discusses their respective strengths and weaknesses. Many of the results presented in this thesis come from comparing the different methods and approximations to exact results. READ MORE