Photodouble ionization beyond the helium case

The study of photodouble ionization (PDI) in He via photoelectron-photoelectron coincidence experiments has made noticeable progresses in the last years. A satisfactory experimental description and a good theoretical understanding have been reached. In this work we show that the same experimental technique provides valuable information on both the direct and indirect PDI processes in the heavier rare gases as well as in molecules. We report some examples of PDI experiments in Ar in equal energy sharing conditions, which probe the different Ar2+ final states at ?20 eV above their respective thresholds. In the case of the Ar2+(3Pe, 1De) states also the PDI in unequal energy sharing condition, at ?40 eV above threshold, has been investigated. The effects of the symmetries of the ejected electron pair and of the indirect process are described. Then the results of energy and angle resolved indirect PDI in CO and N2O are described and discussed.