A unified density-functional treatment of dynamical, nondynamical, and dispersion correlations

In previous work we have introduced exact-exchange-based density-functional models of dynamical, nondynamical, and dispersion correlations. We have not yet, however, been able to combine these models into a single energy functional. The problem is that interaction curves in van der Waals complexes are too repulsive. A simple solution is proposed in the present work resulting in an exact-exchange-based energy functional for all chemical interactions, from the weakest (dispersion) to the strongest (molecular bonds). (C) 2007 American Institute of Physics.