Effect of Self-Energy Corrections on the Valence-Band Photoemission Spectra of Ni

It is shown that the experimentally observed band narrowing, the large quasiparticle damping, the small exchange splitting, and the existence of satellites can be reproduced semiquantitatively with use of the low-density approximation to describe correlations between Ni $3d$ electrons. The exchange splitting of $t_{2g}$ states (~0.37 eV) is found to be considerably larger than that between $e_g$ states (~0.21 eV). A new satellite is predicted about 2 eV below the main "6-eV" satellite.