Scheme for band-structure calculations using an orbital-dependent correlation energy functional

An explicitly orbital-dependent correlation energy functional is proposed for use in band-structure calculations. It is analogous to second-order perturbation terms, and borrows an effective interaction containing long-, intermediate-, and short-range correlation from the electron liquid. Characteristic features of the present correlation energy functional are discussed in connection with its possibility to give an explanation of the electronic structure of strongly correlated electron systems.