Effect of Bound Hole Pairs on the d-Band Photoemission Spectrum of Ni
David R. Penn
It is shown that the spectral density of the Ni d electrons contains a peak due to excitations of bound hole pairs. The spectral density is observed directly in photoemission experiments which show a satellite peak below the bottom of the d bands. The observed peak exhibits a strong resonance as a function of photon energy and this behavior is also explained by the present theory.