Beyond LSDA and Thomas-Fermi: A Hartree-Fock Analysis of Spherical Nanoparticles in the Jellium Approximation

Abstract: A comprehensive Hartree-Fock analysis of the ground-state electronic structure of spherical gold nanoparticles modeled within the jellium approximation is carried out for all systems containing up to 132 delocalized electrons. Emphasis is placed on resolving the energy-level ordering, properly describing the electron density tail and associated charge spill-out, and assessing the accuracy of local exchange and kinetic energy potentials. The calculations are performed on a high-resolution real-space grid to ensure numerical precision. Significant discrepancies are observed between the exchange energy given by the Hartree-Fock approximation and the local spin density approximation (LSDA) in both the inner and outer regions of the nanoparticle. To address these differences, a refined expression of the one-electron exchange energy density as an explicit function of the charge density is proposed. Similarly, the failure of the Thomas-Fermi kinetic energy model near the surface of the nanoparticle is resolved by introducing an improved expression for the one-electron kinetic energy density.