Valence Bond (VB) theory, formulated in the turn of the 1930s, has evolved in parallel with the molecular orbital theory (OM). Both theories led to fundamental developments in chemistry, with VB-based models of reactivity being at the origin of two recent Nobel laureates. VB theory has the advantage of being close to the natural language of chemists, and views the electron pairs of a molecule as located in local bonds or lone pairs. As such, it offers a direct connection between quantum mechanics and usual concepts of molecular chemistry (Lewis structures, resonance, arrow-pushing language, and so on...). This is why it remains a tool of choice for the study of problems of electronic structure and reactivity. Moreover, modern VB ab initio computational methods are now reliable and can provide bonding energies and reaction barriers that are at par with the best standard ab initio computational methods. These two courses will aim at briefly laying the fundations of VB theory, introduce modern ab initio Valence Bond methods, and illustrate their applications in the study of chemical reactivity with a few notable recent applications.
First we have the presentation by Benoît Braida.
... and next we hear Philippe Hiberty...