Dresden 2011 – scientific programme
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A: Fachverband Atomphysik
A 14: Interaction with VUV and X-ray light III
A 14.3: Talk
Friday, March 18, 2011, 11:30–11:45, BAR 106
Non Sequential Double Ionization of Lithium — •Michael Schuricke, Gopisankararao Veeravalli, Christian Dornes, Katharina Joachimsmeyer, Moritz Kurka, Alexander Dorn, and Joachim Ullrich — Max Planck Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg
The most simple and fundamental non-linear multi-electron reaction is double ionization by the absorption of two photons. In a series of benchmark experiments on helium indirect but nonetheless clean information about the distinct reaction channels, in sequential and non sequential double ionization (SDI, NSDI), has been gained by studying the recoil ion momentum. In a new experiment two-photon double ionization of magneto-optically trapped lithium was investigated in a Reaction Microscope (MOT-REMI), again recording the recoil ion momentum with utmost resolution. Due to the structure of lithium with the two tightly bound inner shell and the loosely bound valence electrons, strongly different contributions of the various double ionization mechanisms as compared to helium are expected. While, for example, the NSDI amplitude of helium is partly due to the simultaneous absorption of one photon by each of the electrons, the analogous process is strongly suppressed in the Li(1s22s)+2γ → Li2+(1s) reaction. Here the small binding energy of the outer electron reduces the absorption of vuv-light. Hence, the NSDI amplitude is governed by two-photon absorption of a K-shell electron and electron correlation.