A simple derivation of a simple GGA is presented, in which all parameters (other than those in LSD) are fundamental constants, and only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked.Expand

The influence of a coupling parameter turning on the electron-electron interaction on the difference between Kohn-Sham and Hartree-Fock kinetic and exchange energies is investigated and the formulation and validity of the Hohenberg-Kohn theorem in basis set representations are discussed.Expand

Using a well-known procedure in quantum statistical mechanics for the construction of stationarity principles, the variational principles of Hohenberg, Kohn, and Mermin are obtained as are generalizations thereof.Expand

The Kohn-Sham exchange potential for n is shown, which keeps the exact ground-state density of n, the Hartree-Fock density of H, independent of the coupling constant \ensuremath{\lambda.Expand