Charge-transfer in time-dependent density-functional theory via   spin-symmetry-breaking
  Long-range charge-transfer excitations pose a major challenge for time-dependent density functional approximations. We show that spin-symmetry-breaking offers a simple solution for molecules composed of open-shell fragments, yielding accurate excitations at large separations when the acceptor effectively contains one active electron. Unrestricted exact-exchange and self-interaction-corrected functionals are performed on one-dimensional models and the real LiH molecule within the pseudopotential approximation to demonstrate our results. 
Johanna I. Fuks, Angel Rubio and Neepa T. Maitra
physics.chem-ph cond-mat.other