Heidelberg 2015 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 7: Poster: Atomic systems in external fields

A 7.3: Poster

Montag, 23. März 2015, 17:00–19:00, C/Foyer

Following the evolution of ICD in time — •Fawad Karimi, Martin Ranke, Markus Pfau, Thomas Gebert, and Ulrike Frühling — Institute of experimental physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany

Interatomic Coulombic Decay (ICD) is a non-local auto-ionization process that was predicted by Lorenz Cederbaum in 1997. It is an efficient decay channel used by atoms in loosely bound van der Waals rare gas molecules and clusters. We aim to investigate the ICD lifetime in Neon-Krypton dimers.

The dimers are formed in a co-expansion of a NeKr gas mixture under high pressure through a small aperture in vacuum. In Ne-Kr dimer an ultrashort XUV initiates the ICD by ionizing an inner valence electron of Ne. The relaxation energy of Ne is transferred to Kr atom in form of a virtual photon, which in turn ionizes a 2p Kr electron. The whole process leaves two ionized atoms in a dimer which consequently undergoes a coulomb explosion.

The continuum electron wave packet can be probed with an intense terahertz field, which is superimposed with the XUV pulses (THz-streaking). The change in momentum of electrons due to acceleration in streaking field is proportional to the vector potential of the streaking field at the time of ionization. Thus, the temporal shape of the electron wavepacket is mapped onto changes of electron momenta.