Theoretical chemistry: Back to the valence bond

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 ...

A chemist's guide to valence bond theory

What is the best way to determine bond-valence parameters?

Two recent systematic determinations of bond-valence parameters addressed the problem of the correlation between R0 and b in different ways raising the question of which is to be preferred.

Reinterpretation of the bond-valence model with bond-order formalism: An improved bond-valence-based interatomic potential for PbTiO3

We present a modified bond-valence model of PbTiO3 based on the principles of bond-valence and bond-valence vector conservation. The relationship between the bond-valence model and the bond-order potential is derived analytically in the framework of a tight-binding model. An energy term, bond-valence vector energy, is introduced into the atomistic model and the potential parameters are reoptimi...

Chemical Bonding: The Orthogonal Valence-Bond View

Chemical bonding is the stabilization of a molecular system by charge- and spin-reorganization processes in chemical reactions. These processes are said to be local, because the number of atoms involved is very small. With multi-configurational self-consistent field (MCSCF) wave functions, these processes can be calculated, but the local information is hidden by the delocalized molecular orbita...