Coherence of nondegenerate states studied by auger electron-photoelectron coincidence experiments in Kr.

The indirect double photoionization of Kr via the Kr+(3d(-1)(3/2,5/2)) states to the Kr2+(4s4p(5) (1)P(o)) final state has been studied by Auger electron-photoelectron angular resolved coincidence experiments. By tuning the incident photon energy, we succeeded in observing the coherence in the photoionization of two nondegenerate spin-orbit states. The observations have been described quantitatively by a model which accounts for the two pathways to the final state as well as for the indistinguishability of the two ejected electrons.

Experimental observation of post-collision interaction and interference effects in resonant double photoionization processes.

The combined effects of post-collision interaction in the final state and interference due to the indistinguishability of the two electrons have been studied in a selected case of resonant double photoionization of neon. In our coincidence experiments, the photo- and Auger-electron pair was measured when the two electrons have nearly equal energy and are ejected at small mutual angle. The obtained energy distributions exhibit a strong interplay of post-collision interaction and interference effects, in agreement with the theoretical prediction of Sheinerman and Schmidt [J. Phys. B 30, 1677 (1997)] made on beryllium.