Hannover 2016 – scientific programme
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A: Fachverband Atomphysik
A 22: Interaction with VUV and X-ray light
A 22.7: Poster
Tuesday, March 1, 2016, 16:30–19:00, Empore Lichthof
Real time observation of Interatomic Coulombic decay (ICD) in Ar dimers with XUV-pump IR-probe experiments — •Tomoya Mizuno, Philipp Cörlin, Andreas Fischer, Michael Schönwald, Lukas Palm, Thomas Pfeifer, and Robert Moshammer — Max-Planck-Institut für Kernphysik, Heidelberg, Germany
We determined the ICD lifetime of Ar dimers by using XUV-pump IR-probe experiments. The first XUV pulse, which is generated from a 10 fs IR laser pulse via HHG in Ar gas, creates the lowly excited ionic states, which can decay rapidly via ICD leading to a dissociative kinetic energy release (KER) of 3.8 eV. Afterwards, the delayed IR probe pulse further ionizes into dicationic states at one site (Ar2+-Ar) or excite into highly excited states if the ICD did not occur yet. These states are long lived, therefore contraction of the dimers occurs. Then these states decay via radiative charge transfer and ICD respectively, resulting in a high KER of 5.2 eV. Finally, the ion pair emerging from the Ar dimer is detected by a reaction microscope. The apparatus enables us to record the ion yield of Ar+ +Ar+ ion pairs as a function of the pump-probe delay and KER. We found that the delay-dependent ion yield at a KER of 5.2 eV shows an exponential decay with a time constant of 30.1±8.4 fs. We assigned this time constant to the ICD lifetime of the Ar+*(3p−2(1D)3d 2D)-Ar state based on the photoionization cross section and the potential energy curves. This is in good agreement with previous calculations of 28 fs [1].
[1]T. Miteva et. al. JCP 141, 064307 (2014)