Then, instead of complaining about "the idiosyncratic be- Kohn-Sham (GKS) and the generalized optimized effective potential (GOEP, which has been shown to be equivalent to orbital optimization (OO) Jin et al. ). Three properties of each quantity are considered for each computational approach: (1) Agreement of ρ σ s (r), the density of the noninteracting reference system, with ρ σ (r), the density of the physical system consistent with the exact DFT, or the density of the DFA as defined by the linear response • (a) In an inverse calculation, the potential is determined up to an arbitrary constant and the absolute values of the orbital energies are therefore undefined. However, if the correct asymptotic condition on the potential is imposed, which also sets the constant, then ε H = -I, is obtained, where I is the experimental ionization energy Parr and Yang .