Rostock 2019 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 34: Interaction with VUV and X-ray light
A 34.7: Poster
Donnerstag, 14. März 2019, 16:15–18:15, S Fobau Physik
Two photon double ionization in Neon — •Severin Meister1, Kirsten Schnorr2, Sven Augustin1, Hannes Lindenblatt1, Florian Trost1, Yifan Liu1, Claus-Dieter Schröter1, Thomas Pfeifer1, and Robert Moshammer1 — 1Max-Planck-Institut für Kernphysik — 2Paul Scherrer Institut
The angular distribution of electrons, which are emitted in the course of an ionization process, comprises much information about the atom. Double ionization of noble gases has been exclusively achieved by absorbing a single photon with an energy above the double ionization potential. However with the emergence of intense light sources in the extreme ultra violet regime, i.e. Free Electron Lasers, absorbing two photons became feasable. In addition, an adjustable time delay between the two photons allows to investigate time dependent effects. Therefore the presented experiment was carried out at the Free Electron Laser in Hamburg (FLASH2), with a split and delay mirror geometry. The Neon atom absorbes successively two photons, while their delay can be adjusted. In this manner the two electrons are also emitted successively, which discriminates the process from the single photon case. The scheme allows to investigate the dynamics of the two superposed states 2P1/2, 2P2/3 in the intermediate Ne+ ion by measuring the delay dependent angular distribution of the second electron. Another interesting aspect we are adressing is that the angular distribution of the first electron is predicted to depend on the emission angle of the second one, which stands in contrast to the simple picture of sequential ionization.