The exchange energy between neon atoms

Abstract

The exchange energy of Ne₂ is calculated from an antisymmetrized product of Ne SCF wave functions in the range 4–8 bohr. Taking the best SCF orbitals (near Hartree-Fock) as standard, the single Slater basis gives energies that are considerably different in this range, and even the double-zeta basis gives energies that differ by a factor of five at the upper limit of the range. A combination of the best Clementi energy with the multipolar expression for the dispersion energy (up to R ^-10) gives a potential curve in good agreement with that deduced from experimental data