Insights into the electronic structure of molecules from Generalized Valence Bond theory - Thomas Harold Dunning

Generalized Valence Bond (GVB) theory provides a compelling description of the electronic structure of molecules. The GVB wave function is more accurate than the Hartree-Fock (molecular orbital) wave function, including the major non-dynamical correlation effects present in the valence complete active space self-consistent field (CASSCF) wave function. Unlike other multiconfiguration wave functions, the GVB wave function – through the changes in the orbitals, spin couplings and overlaps – provides unparalleled insights into the bonding, structure, and energetics of molecules. We will discuss a number of examples that illustrate the power of the GVB approach, including bonding in hypervalent molecules (SF4/SF6), vertex versus edge inversion in the PHnF(3-n) series, and the potential energy surface for the reaction of F2 with dimethylsulfide.