State-selective study of the direct double photoionization of the Ne valence shell

Cross sections for double photoionization of the Ne L shell into the 2s2p5 3P0 and 1P0 and the 2s02p6 1Se states were measured for energies from threshold up to 150 eV, using photon induced fluorescence spectroscopy. Both 2s2p5 channels were observed with comparable magnitude in contradiction to a propensity rule based on the Wannier-Peterkop-Rau theory. A comparison of the summed 3P0 and 1P0 cross sections with MBPT calculations results in a deviation of 50%.