SPIN-RESOLVED TRIPLE DIFFERENTIAL CROSS-SECTIONS OF XENON

Spin-resolved triple differential (e,2e) cross sections have been meas ured for ionization of xenon atoms by polarized electrons for energies between 40 and 200 eV. Significant spin up-down asymmetries in the (e , 2e) cross sections have been obtained at all energies. These are dom inated by the interplay of orbital orientation, fine-structure interac tion and exchange of the colliding electrons ('fine-structure effect') , whereas the influence of relativistic orbitals and of the continuum spin-orbit interaction is less important. The results are compared wit h recent DWBA calculations that include exchange with the electrons of the residual ion (exchange distortion), and satisfactory agreement is found. In particular, the discrepancies between theory and experiment at 40 eV and symmetric energy sharing are resolved.