Multiple excitation at xenon 5sphotoionization threshold

The effect of multiple electron excitation on the threshold behavior of Xe 5s photoionization is studied using the multichannel multiconfiguration Dirac-Fock method with full account of relaxation. The inclusion of the ionization channels related to 5p⁴5d Jion=(1/2 excited states is found to change the single-excitation results drastically. Our cross section and asymmetry parameter {β} are in very good agreement with experiment. Calculation of the related satellite cross sections predicts a new type of satellite that exists only in the near-threshold region and has a peculiar angular dependence.