Multielectron effects in photoemission from quasi-atomic copper in Cu-phthalocyanine

Photoelectron energy distribution curves for Cu in Cu-Phthalocyanine have been investigated around the Cu 3p threshold at hv = 75 eV. A sharp 3d-electron satellite with two peaks with initial energies of 5.5 and 8.5 eV below the center of the Cu 3d main peak was found which exhibits a strong resonant enhancement at threshold. These results are explained as a two-electron shake-up multiplet with a 3p63d84s2 + e- final state configuration. The results are compared with metallic Cu, and the different chemical, relaxation (screening) and configuration shifts are discussed. © 1980.