Many-body and model-potential calculations of low-energy photoionization parameters for francium

Abstract

The photoionization cross section [Formula Presented] spin-polarization parameters P and Q, and the angular-distribution asymmetry parameter [Formula Presented] are calculated for the [Formula Presented] state of francium for photon energies below 10 eV. Two distinct calculations are presented, one based on many-body perturbation theory and another based on the model potential method. Although predictions of the two calculations are similar, the detailed energy dependences of the photoionization parameters from the two calculations differ. From the theoretical p-wave phase shifts, we infer quantum defects for [Formula Presented] and [Formula Presented] Rydberg series, permitting us to calculate positions of experimentally unknown p states in francium. © 2000 The American Physical Society.