KOHN-SHAM DENSITY-FUNCTIONAL THEORY WITHIN A FINITE BASIS SET

The Kohn-Sham self-consistent equations, using a finite orbital basis expansion, are formulated for exchange-correlation functionals which depend on local densities and their gradients. It is shown that these can be solved iteratively without evaluation of density Hessians. A general expression is given for the energy gradient (with respect to nuclear motion) after self-consistency has been achieved.