INTERPRETATION OF RARE-EARTH ION YIELDS USING AN EFFECTIVE POTENTIAL APPROACH

We use a simple potential well model to study the 4d --> 4f giant reso nances in Ce, Sm, Eu and Gd. We show that photoionization of a d elect ron in a spherical potential well into a short-lived quasibound f stat e produces the observed asymmetric ion yield curves. In our approach a suitable normalization condition is applied to the final state wavefu nction inside the well and it is assumed that the f electron escapes w ithin a very short time from the well. We further show that our three- parameter model allows the resonance profiles to be parametrized accor ding to the Fano profile of the photoionization cross section.