Kinetic Energies and Exchange Model Potentials Calculated with a Simple Analytical Representation of Atomic Densities

Abstract

A simple analytical representation of Hartree-Fock atomic densities recently devised defines ρ(r) as a sum of exponentially decaying functions. This basis set-independent representation is here applied to the calculation of kinetic energies, making use of various well-known kinetic energy functionals. Despite its extreme simplicity, these functions provide highly reliable representations of ρ(r), allowing the calculation of kinetic energies to within 1% or less. This representation of the density is also analyzed in exchange-only functional calculations. A semiempirical model exchange potential developed before (Pacios, L. F. J. Phys. Chem. 1992, 96, 7294) is here modified and analyzed