Valence bond-configuration interaction

This is a simple example of valence bond configuration interaction. 

W. Wu, L. Song, Z. Cao, Q. Zhang, S. Shaik, J. Phys. Chem. A 106, 2721 (2002). Valence Bond Configuration Interaction A Practical Valence Bond Method Incorporating Dynamic Correlation. 

VBCI Valence bond configuration interaction. A VB computational method that starts with a VBSCF wave function, which is further improved by CI. The Cl involves virtual orbitals that are localized on exactly the same regions as the respective active orbitals. There are a few VBCI levels that are denoted by the rank of excitation into the virtual orbitals, for example, VBCISD involves single and double excitations. 

The geometric and electronic structures of the mononuclear [Cu(02)(TpAd,pr)] complex have been evaluated using Cu K- and L-edge X-ray absorption spectroscopy (XAS) studies in combination with valence bond configuration interaction (VBCI) simulations and spin-unrestricted broken symmetry density functional theory (DFT) calculations.205... 

Fig. 4. Generalised Valence Bond Configuration Interaction relative free energies for the addition of olefin to Cr02Cl2 showing that addition across a single Cr=0 bond is favoured. (Derived from Fig. 10 of Ref. 95a)...

Valence Bond Configuration Interaction Model (VBCI)... 

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