Electron localization function comparative study of ground state, triplet state, radical anion, and cation in model carbonyl and imine compounds

The modifications of bonding in carbonyl and imine compounds upon excitatio n, electron attachment, and ionization were studied within the framework of the electron localization function (ELF). The topological analysis of ELF allows a partition of the molecular space into regions having a clear chemi cal meaning: the basins. The electronic populations of the basins associate d with bonding and nonbonding character, as well as the basin spin densitie s, were calculated at the MP2 level of the quantum mechanical calculation. Good agreement was found with the classical view in terms of mesomeric stru ctures corresponding to the dominant localization of electrons contained in frontier molecular orbitals (MOs). The variations of the basins population were compared to the predictions of MO theory. (C) 1999 John Wiley & Sons, Inc.