VB-DFT: A nonempirical hybrid method combining valence bond theory and density functional energies

A nonempirical procedure is presented for combining the Valence bond (VB) m ethodology with density functional theory (DFT). The method, called VB-DFT, is based on partitioning the system into two coupled electronic subsets, o ne treated by DFT and the other by VB theory. The DFT energy component incl udes the exchange correlation potential while the coupling involves electro n repulsion and exchange interactions. Tests and applications show that the VB-DFT hybrid method has the qualities of a VB method along with a quantit ative advantage over VB-only methods with traditional core-valence separati on. (C) 1999 Elsevier Science B.V. All rights reserved.