ELECTRONIC AND NUCLEAR-CHEMICAL REACTIVITY

The local softness and the Fukui function emerge from density function al theory as measures of local electronic reactivity. We obtain here a n exact linear integral relation between the Fukui functions of insula tors or molecules and the probability density of the frontier orbitals of Kohn-Sham theory. The same linear map holds between the local soft ness and the local Kohn-Sham density of states at the Fermi level for metals. The kernel in those relations is the inverse of the transpose of the potential response function (PRF) of Kohn-Sham theory. The PRF has the form of the static Hartree dielectric function with an exchang e and correlation interaction added to the bare Coulomb interaction. T he exact static dielectric function also has the Hartree form, but wit h a renormalized polarization propagator. The map is norm preserving f or systems with energy gaps such as insulators and molecules and norm reducing or screening for systems with a finite density of states abov e the ground state such as normal metals and Anderson insulators. Nucl ear reactivities are defined in analogy with the more familiar electro nic reactivities and are more directly relevant to reaction pathways. The former are linearly related to the frontier orbital densities or t he local density of states through a kernel which is just the electron -nuclear Coulomb force screened by the PRE This shows explicitly how t he frontier orbital density or the local density of states drives the nuclear reactivity. The limitations of such definitions of chemical re activity are discussed and directions for improvement indicated.