Description of electron delocalization via the analysis of molecular fields

The methodologies available to analyze molecular fields that are suitable descriptors of chemical bonding and electron delocalization are reviewed. Focus is on the mathematical and physical concepts necessary to perform the topological analysis of a molecular field. Several molecular fields relevant in chemistry to obtain information on the chemical bonding and, especially, on electron delocalization and electron localization, are discussed in detail. The fields include the electron density, its Laplacian, the Fermi hole, the electrostatic potential, and a few other less common molecular fields.