Photoion yield spectroscopy in the 4d photoionization of

Abstract

Using an ion-photon merged-beam apparatus, photoion yield spectra of and from the 4d photoionization of were measured as a function of photon energy in the range 110-160 eV. The measured spectra look very similar to those from a neutral Eu target. Both and yield spectra, a broad `giant resonance' appears at 140 eV with some preceding small peaks at 131.5, 132.8 and 134.7 eV. The summit of the `giant resonance' in the spectrum is split into two peaks. This is not observed in neutral Eu photoionization.