Optimized effective potential method

The optimized effective potential method (OEP) in Kohn-Sham (KS) density functional theory (DFT) is a method to determine the potentials as functional derivatives of the corresponding KS orbital-dependent energy density functionals. This can be in principle done for any arbitrary orbital-dependent functional, but is most common for exchange energy as the so-called exact exchange method (EXX), which will be considered here.