[show abstract][hide abstract] ABSTRACT: The question of whether the Hohenberg–Kohn–Sham version of density functional theory (HKS-DFT), a semi-empirical theory is treated by resorting to an analysis of its foundations. In particular, it is shown that the construction of the universal functional F[ρ] in HKS-DFT is equivalent to solving the N representability problem for the 2-matrix. Also, the relationship between the Hohenberg–Kohn theorem and the Legendre transformation is discussed and some of the positions concerning the N-dependence (or N-independence) of the universal functional are presented. Finally, some comments are made concerning the reasons why in many cases HKS-DFT turns out to be so highly successful.
Journal of Molecular Structure THEOCHEM 01/2004; 709:25-29.