Fukui function

In computational chemistry, the Fukui function or frontier function is a function that describes the electron density in a frontier orbital, as a result of a small change in the total number of electrons. The condensed Fukui function or condensed reactivity indicator is the same idea, but applied to an atom within a molecule, rather than a point in three-dimensional space. In computational chemistry, the Fukui function or frontier function is a function that describes the electron density in a frontier orbital, as a result of a small change in the total number of electrons. The condensed Fukui function or condensed reactivity indicator is the same idea, but applied to an atom within a molecule, rather than a point in three-dimensional space. The Fukui function allows one to predict, using density functional theory, where the most electrophilic and nucleophilic sites of a molecule are. The Fukui function is named after Kenichi Fukui, who investigated the frontier orbitals described by the function, specifically the HOMO and LUMO. Fukui functions are related in part to the frontier molecular orbital theory (also known as the Fukui theory of reactivity and selection, also developed by Kenichi Fukui) which discusses how nucleophiles attack the HOMO while at the same time placing their surplus electrons into the LUMO.