  We introduce a new functional for simulating ground-state and time-dependent
electronic systems within density-functional theory. The functional combines an
expression for the exact Kohn-Sham (KS) potential in the limit of complete
electron localization with a measure of the actual localization. We find
accurate self-consistent charge densities, even for systems where the exact
exchange-correlation potential exhibits non-local dependence on the density,
such as potential steps. We compare our results to the exact KS potential for
each system. The self-interaction correction is accurately described, avoiding
the need for orbital-dependent potentials.
