Difficulties in the Valence Bond Theory

A chemist's guide to valence bond theory

Essay Valence Bond Theory for Chemical Dynamics

This essay provides a perspective on several issues in valence bond theory: the physical significance of semilocal bonding orbitals, the capability of valence bond concepts to explain systems with multireferences character, the use of valence bond theory to provide analytical representations of potential energy surfaces for chemical dynamics by the method of semiempirical valence bond potential...

The Valence Bond Glass phase

We show that a new glassy phase can emerge in presence of strong magnetic frustration and quantum fluctuations. It is a Valence Bond Glass. We study its properties solving the Hubbard-Heisenberg model on a Bethe lattice within the large N limit introduced by Affleck and Marston. We work out the phase diagram that contains Fermi liquid, dimer and valence bond glass phases. This new glassy phase ...

Valence-bond theory of compounds of transition metals.

An equation relating the strength (bondforming power) of an spd hybrid bond orbital to the angles it makes with other bond orbitals is formulated and applied in the discussion of the structures of transition-metal carbonyls and other substances by the valence-bond method. The rather simple theory gives results that agree well with those obtained by the complicated and laborious calculation of s...

Theory of Valence-bond Lattice on Spin Lattices*

Quantum spin-lattice systems in low dimensions exhibit a variety of interesting zero-temperature phases, some of which show non-classical (i.e., non-magnetic) long-range orders, such as dimer or trimer valence-bond order. These symmetry-breaking systems with localized valence bonds are referred to as valence-bond lattices (VBL) in this article. A review of our systematic microscopic formalism b...