SIMPLER EXPRESSION FOR EVALUATING THE DENSITY MATRIX IN THE SELF-CONSISTENT GREEN-FUNCTION METHOD

In a recent publication describing a self-consistent Green's function for use in studying defects in solids, one of the major steps was evaluating the density matrix mn which describes the valence charge density in a basis of localized orbitals. We have since discovered an algebraic identity which considerably simplifies that evaluation, and we here present the simplified form for mn. © 1979 The American Physical Society.