It has been observed that the photoexcited M3M4,5M4,5(G1) Auger line in Zn asymmetrically broadens to lower energy with increasing photon energy. The broadening can be described by a change in the asymmetry parameter=0.09 in a Doniach-Sunjic line shape. This is the first evidence for the transition from the adiabatic to the sudden regime in a solid. The onset of this change 14 eV above threshold is related to 3d screening electron excitations which are seen as 3p core-level satellites. © 1980 The American Physical Society.