INTERFERENCE EFFECTS IN INNER-SHELL DOUBLE PHOTOIONIZATION OF XENON

We present measurements and calculations of triple differential cross sections (TDCSs) for indirect double photoionization of xenon due to 4 d(5/2) inner-shell ionization and Auger decay. The interference effect s, which occur when the energies of the photoelectron and Auger electr on are equal to each other, are studied extensively by exploring sever al Auger lines. The related TDCS patterns appear to be governed by the symmetry of the residual ion: for antiparallel emission the interfere nce is destructive for all states of S-1(e) symmetry, whereas it is ob served for the first time to be constructive for the state of P-1(o) s ymmetry which has been selected. The calculated TDCSs, which are based upon expressions derived by Vegh and Macek (Vegh L and Macek J H 1994 Phys. Rev. A 50 4031) and on asymmetry parameters for the Auger and 4 d(5/2) photo-electrons given in the literature, appear to be in good a greement with the experiments and allow us to investigate the interfer ence effects in more detail.