Electron Correlation Energies in the Neutral Iron Atom

Abstract

The many-body perturbation theory of Brueckner and Goldstone is used to calculate the electron correlation energy among the $n=3\mathrm{}$ and $n=4\mathrm{}$ electrons of FeI. The results is - 0.7155 a.u. Combined with a semiempirical estimate of correlations from the ${\mathrm{}\left(1s\right)\mathrm{}}^2{\mathrm{}\left(2s\right)\mathrm{}}^2{\mathrm{}\left(2p\right)\mathrm{}}^6$ core, the total correlation energy of FeI is - 1.165 a.u.