Why are the band-like states suppressed in the M3-M4,5M4,5 super Coster-Kronig electron spectrum of Cu metal compared to those in the L3-M4,5M4,5 Auger electron spectrum?

The relative spectral intensity of the band-like two M4,5-hole state to the atomic-like localized one is much suppressed in the coincidence M3-M4,5M4,5 super Coster-Kronig (sCK) electron spectrum of Cu metal compared to the one in the coincidence L3-M4,5M4,5 Auger electron spectroscopy (AES) spectrum. The M3-hole lifetime width of Cu metal is calculated by an ab initio atomic many-body theory (the extended relaxed core random phase approximation with exchange). The calculated M3-hole lifetime width of Cu metal agrees well with the experimental one. The M3-M4,5M4,5 sCK decay width of Cu metal decreases much with delocalization of the two M4,5 holes in the sCK final state, whereas the Auger decay width is fairly independent of localization and delocalization of the two M4,5 holes in the Auger final state. Thus, the relative spectral intensity of the band-like state is much suppressed in the coincidence M3-M4,5M4,5 sCK-electron spectrum of Cu metal compared to the one in the coincidence L3-M4,5M4,5 AES spectrum.