Resonance photoemission is discussed for the Cu 3d emission in Nd2CuO4, the Ce 4f emission in Ce compounds and the U 5f emission in UO2, which have qualitatively different resonance behaviors. These behaviors can be understood within the Anderson impurity model. For both the Ce compounds and UO2, interference effects between the intermediate configurations play an important role. The differences between these systems is due to their entirely different parameter ranges. For Cu2+ compounds one intermediate configuration dominates, leading to a third type of resonance behavior.
 

Physica Scripta, T41 12-18, 1992.