The bond energy challenge has already been met by VB theory, and accurate bond energies may be obtained by VB treatments such as the breathing orbital VB method (BOVB).  However, highly accurate reaction barrier calculations are still challenging for VB theory.
A spinfree form of valence bond theory - McWeeny - 1988 Classical valence bond theory is recast in a spinfree form which provides a practicable route to ab initio calculations of molecular electronic structure.
Jan 01, 2013 · Modern classical valence bond (VB) methods provide clear interpretation and chemical insights by employing covalent and ionic VB structures explicitly. This review focuses on a methodical development of current modern classical VB methods. As a basic method of the classical VB theory, the VB selfconsistent field (VBSCF) method provides a compact wave function, mainly containing
Classical structures in modern valence bond theory Mar 01, 1988 · The results of some recent ab initio valence bond calculations, in which both structure coefficients and orbital forms are optimized, are analysed. The origin of structures in which the optimum orbitals are no longer atomic in character but instead delocalized, is traced back to the presence of certain symmetries in the wavefunction. When such symmetries exist it is possible to choose
Modern Ab Initio Valence Bond Methods Solving the Quantum mechanics has provided chemistry with two general theories of bonding:valence bond (VB) theory and molecular orbital (MO) theory. VB theory is essentially a quantum mechanical formulation of the classical concept of the chemical bond wherein the molecule is regarded as a set of atoms held together by local bonds.
The method aims at combining the properties of interpretability and compactness of the classical valence bond method with a reasonable accuracy of the energetics. All Lewis structures relevant to the electronic system are generated, each of them being described by a single valence bond
Valence Bond Methods - cambridgeShurki, Avital Hiberty, Philippe C. Dijkstra, Fokke and Shaik, Sason 2003. Aromaticity and antiaromaticity:what role do ionic configurations play in delocalization and induction of magnetic properties?. Journal of Physical Organic Chemistry, Vol. 16, Issue. 10, p. 731
Valence-bond calculation of the electronic structure of electronic delocalization:a quantitative study from modern ab initio valence bond theory. Journal of Theoretical and Computational Chemistry 2002 , 01 (01) , 137-151.