Density functional theory and f electron systems

Density functional theory within the local density approximation has proven to be an extremely successful way to elucidate the electronic structure and ground state properties of a wide variety of electronic systems. Because of the discovery of exotic behavior in f electron systems such as the mixed valent effect and heavy fermion phenomenon, the applicability of the above theory has been questioned. Recently, dramatic progress has been made in determining more exact density functionals which have been extensively tested in atomic systems. The purpose of this paper is to speculate what impact these new methods will have on the f electron question. In the first section, a brief review of density functional theory and the local density approximation (LDA) is given, as well as an equally brief review of results on f electron solids. In the second section, the new density functional techniques are discussed and results for atoms reviewed, and potential extension of these methods to the case of the lattice, with emphasis on f electron solids is presented