Experimental (e,2e) study of resonant Auger states of Ar

We present a short review of our (e,2e) measurements of electrons emitted after 2p inner-shell excitation of argon. The LMM Auger electrons are measured in coincidence with the scattered electrons, producing the considered excited state. Particularly the 2p3/2→4s3/2 and the dipole forbidden 2p3/2→4p3/2 excitations are studied. The strongest resonant Auger transitions from [2p3/2]4s and 4p states are reliably identified in the spectra. A considerable contribution of the direct process, leading to the same final state is measured separately. The removal of this contribution - as a background - was found problematic because of a quantum mechanical interference between the direct and indirect processes.