Resonant photoemission shake-up and Auger processes at the 3p photothreshold in Ga and GaP

Resonant photoemission 3d⁸ shake-up satellites in Ga metal and GaP, which are closely related to M2,3M4,5M4,5 Auger transitions, have been observed at the $3p$ photothreshold of Ga. By analyzing the line positions, multiplet structure, and resonant behavior near threshold, we have determined the excitonic binding energies and correlation energies for various one-hole and two-hole excited states. While these two-hole excitations in Ga metal and GaP are similar because of their quasiatomic nature, important differences are observed which are due to different final-state screening mechanisms for a metal and an insulator. The present results are compared with those for Cu and Ni.