Measurements of absolute Ar 3<i>s</i>photoionization cross sections

Abstract

Cross sections for the photoionization of the argon 3s electron are presented from threshold up to 100 eV. In order to cover this whole energy range with comparable accuracy, we used two complementary methods: absolute measurements by photon-induced fluorescence spectroscopy (PIFS) and relative measurements by time-of-flight (TOF) photoelectron spectroscopy (PES). After calibration of the relative PES data by the most recent absorption results, the data of these independent measurements agree well with each other. The experiments were carried out with special emphasis to the threshold region (PIFS) and the region of the cross sectional minimum (TOF) where, in addition to the partial cross sections, the angular distributions of the photoelectrons were determined. The results are compared with published data and discussed with respect to matrix-element dependencies and correlation effects.