Sökning: "Trygve Helgaker"

Hittade 2 avhandlingar innehållade orden Trygve Helgaker.

  1. 1. Foundation of Density Functionals in the Presence of Magnetic Field

    Författare :Andre Laestadius; Michael Benedicks; Trygve Helgaker; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Current density functional theory; Hohenberg-Kohn theorems; paramagnetic current density functionals; Kohn-Sham theory; Levy-Lieb functional; variational principle; N-representable; degeneracy; Matematik; Mathematics;

    Sammanfattning : This thesis contains four articles related to mathematical aspects of Density Functional Theory.In Paper A, the theoretical justification of density methods formulated with current densities is addressed. It is shown that the set of ground-states is determined by the ensemble-representable particle and paramagnetic current density. LÄS MER

  2. 2. Studies of Self-interaction Corrections in Density Functional Theory

    Författare :Guangde Tu; Olav Vahtras; Trygve Helgaker; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; Teoretisk kemi;

    Sammanfattning : The self-interaction error (SIE) in density functional theory (DFT) appears from the fact that the residual self-interaction in the Coulomb part and that in the exchange part do not cancel each other exactly. This error is responsible for the unphysical orbital energies of DFT and the failure to reproduce the potential energy curves of several physical processes. LÄS MER