Postcollision Interaction in the Coincident Emission of Photoelectrons and Auger Electrons at Small Relative Angles

Postcollision interaction effects have been investigated for sequential two-electron emission in xenon for particular kinematical conditions, small relative angles between the emitted electrons, and selected energies ε_a = ε_b which are halfway in between the nominal values of the “photo”-electron and the “Auger” electron. The experimental results are in good agreement with the theoretical prediction. Our successful technique to measure two coincident electrons of nearly the same energy and the same directions opens a plethora of possibilities to probe for different cases the Coulomb interaction of three charged particles and the impact of the intermediate resonance state.