A unified view of resonant photoemission of metallic, molecular, and correlated solid systems

We have investigated the resonant behavior of Ni 3p and 3s satellite photoe lectrons at Ni 2p edges for different solid systems. In Ni metal, above the Ni 2p resonance maximum the enhanced satellite electrons have nearly the s ame kinetic energies as the normal Auger electrons. In K2Ni(CN)(4), as a mo lecular system, the enhanced satellite electrons lower their kinetic energy for the higher resonance energy, converging to the normal Auger energy aro und the Ni 2p ionization threshold. These results indicate that the satelli te states have electronic structures with insufficiently and sufficiently l ocalized character in the metallic and molecular systems, respectively. In NiO, as a correlated system, resonantly enhanced satellites show nearly con stant binding energies and the normal Auger electrons are emitted independe ntly of the satellite electrons. This is characteristic of a correlated sys tem. (C) 1999 Elsevier Science B.V. All rights reserved.