  We present an improved approach for generating a set of optimized frontier
orbitals (HOMO and LUMO) that minimizes the energy of one double configuration.
We further benchmark the effect of including such a double within a CIS or
TD-DFT configuration interaction Hamiltonian for a set of test cases. We find
that, although we cannot achieve quantitative accuracy, the algorithm is quite
robust and routinely delivers an enormous qualitative improvement to standard
single-reference electronic structure calculations.
