Chemical reactivity indexes in density functional theory

The theoretical description of charge distribution, and related properties, such as chemical reactivity descriptors of chemical compounds, has greatly benefited from the development of density functional theory (DFT) methods. Indeed, most concepts stemmed from DET but, up to now, they have been used mostly within semiempirical MO methods, Hartree-Fock, or post-Hartree-Fock methods. During the last decade, however, DET has enabled theoretical chem istry to predict accurately structures and energetics of clusters and molec ules. Therefore, more attention should also now be paid to these reactivity descriptors determined directly from DET calculations. In this work, chemi cal reactivity is explored in DFT through a functional Taylor expansion of energy that introduces various energy derivatives of chemical significance. This review summarizes their main features and examines the limitations of some indexes presently used for the characterization of reactivity. Also, several perspectives are given. (C) 1999 John Wiley & Sons, Inc.