Spin-polarization measurements of the krypton M_4,5NN and xenon N_4,5OO Auger electrons: Orientation and intrinsic parameters

In the framework of the two-step model of Auger decay the orientation of the krypton 3d^-1 and xenon 4d^-1 primary hole states has been determined as a function of photon energy. This was achieved by carrying out spin-polarization measurements of the Kr M_4,5N_2,3N_2,3 and Xe N_4,5O_2,3O_2,3 Auger electrons after ionization of free atoms by circularly polarized synchrotron radiation of 130–530 eV photon energy. The orientation parameter is found to be strongly influenced by the Cooper minimum in the Xe 4d photoionization cross section as demonstrated by the comparison of the Kr and Xe data. Furthermore, the intrinsic parameters for all lines in the Kr M_4,5N_2,3N_2,3 and Xe N_4,5O_2,3O_2,3 Auger groups and for several lines in the Kr M_4,5N₁N_2,3 Auger group were determined with high accuracy and are compared with previous experiments and calculations. We were also able to measure the spin polarization of most of the low kinetic-energy Kr M_4,5NN and Xe N_4,5OO lines, showing that the assignment of one of the lines should be revisited.