Angular distribution of Kr4s→εp photoelectrons: a test of current theory

Abstract
The angular asymmetry parameter beta for Kr 4s to epsilon p photoelectrons has been studied using synchrotron radiation (hv=31-63.5 eV). The present results show that earlier calculations based on the relativistic random-phase approximation (RRPA) do not satisfactorily describe the Kr 4s photoionisation process close to the Cooper minimum. This lack of agreement has also been found recently for the Xe 5s excitation. The experimental results are compared with a new, not yet published, theoretical approach which gives good agreement with experiment.