Adiabatic connection approach to density functional theory of electronic systems

Using recent calculations we review some well-known aspects of density functional theory: the Hohenberg-Kohn theorems, the Kohn-Sham method, the adiabatic connection and the approximations of local nature. Emphasis is put upon using model Hamiltonians, of which the noninteracting or the physical ones are just particular cases. The model Hamiltonians allow us to produce multireference density functional theory and continuously switch to the physical system. (C) 2003 Wiley Periodical Inc.