Van der Waals interactions in density functional theory
Boese, Adrian Daniel
Scuseria, Gustavo E.
Master of Science
Various density functional methods have been tested for the van der Waals interactions of the rare gas dimers He$\rm\sb2,\ Ne\sb2$ and Ar$\sb2$ as model compounds. Detailed analysis proved that all tested and commonly used functionals are not suitable for an appropriate description of the interactions, even if Hartree-Fock exchange is used in combination with a correlation functional. However, within the framework of long-range density functional theory, van der Waals coefficients are correctly reproduced by a density-density interaction term. Adding these interactions separately to the tested functionals, surprisingly good results are obtained by using exact exchange.