Angle-resolved 2D imaging of electron emission processes in atoms and molecules

A variety of electron emission processes have been studied in detail for both atomic and molecular systems, using a highly efficient experimental system comprising two time-of-flight (TOF) rotatable electron energy analyzers and a 3rd generation synchrotron light source. Two examples are used here to illustrate the obtained results. Firstly, electron emissions in the the HCL molecule have been mapped over a 14 eV wide photon energy range over the Cl 2p ionization threshold. Particular attention is paid to the dissociative core-excited states, for which the Auger electron emission shows photon energy dependent features. Also, the evolution of resonant Auger to the normal Auger decay distorted by post-collision interaction has been observed and the resonating behavior of the valence photoelectron lines studied. Secondly, an atomic system, neon, in which exciation of doubly excited states and their subsequent decay to various accessible ionic states has been studied. Since these processes only occurs via inter-electron correlations, the many body dynamics of an atom can be probed, revealing relativistic effects, suprising in such a light atom. Angular distribution of the decay of the resoances to the parity unfavored continuum exhibits significant deviation fro the LS coupling predictions