Exchange interference between coincident photoelectrons and Auger electrons

For the sequential process of coincident photoelectron and Auger electron e mission it is demonstrated that electron exchange and post-collision intera ction can lead, due to constructive interference effects, to a remarkably i ntense third line. The selected example is 4d(5/2) photoionization in xenon with subsequent N-5-O2,3O2,3 S-1(0) Auger decay. Here the photoelectron li ne is placed 25 units of the width of the intermediate hole-state below the Auger electron line, and the relative angle between, the emitted electrons is set to 12 degrees. The quantitative agreement between experimental data and theoretical results, obtained in the one-step model, confirms the theo retical treatment for a critical case of correlated two-electron emission.