  It is observed that the exact interacting ground-state electronic energy of
interest may be obtained directly, in principle, as a simple sum of orbital
energies when a universal density-dependent term is added to $w\left(\left[
\rho \right];\mathbf{r} \right)$, the familiar Hartree plus
exchange-correlation component in the Kohn-Sham effective potential. The
resultant shifted potential, $\bar{w}\left(\left[ \rho \right];\mathbf{r}
\right)$, actually changes less on average than $w\left(\left[ \rho
\right];\mathbf{r} \right)$ when the density changes, including the fact that
$\bar{w}\left(\left[ \rho \right];\mathbf{r} \right)$ does not undergo a
discontinuity when the number of electrons increases through an integer. Thus
the approximation of $\bar{w}\left(\left[ \rho \right];\mathbf{r} \right)$
represents an alternative direct approach for the approximation of the
ground-state energy and density.
