Erlangen 2018 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 25: Poster Session I

A 25.13: Poster

Dienstag, 6. März 2018, 16:15–18:15, Redoutensaal

Transitions above (and near) the ionisation threshold — •Anne Harth, Robert Moshammer, and Thomas Pfeifer — Max-Planck-Institut für Kernphysik, Heidelberg, Deutschland

Photoionization is a fundamental and still extensively discussed process, where an electron is removed from e.g. an atom by a high-energy photon. Recently, it was possible to measure a photoionization phase shift between a single electron coming from the 2s or 2p state in a neon atom [1,2]. Such a phase shift can be interpreted as a time delay that is on the order of only a few attoseconds.

However, the kinetic energy of such a released electron depends on the photon energy and the ionisation potential. A slow electron, which is still in the influence of its mother ion, can absorb additional photons. The dipole matrix element, which describes the additional photoabsorption in the continuum, is often either neglected or calculated [4] and was not experimentally studied so far, but plays an important role e.g. in the above mentioned photoionization experiment in Neon [2,3].

We propose and discuss a multi-color electron wave packet interferometer to experimentally study the near ionisation threshold continuum including continuum-continuum dipole transitions matrix elements.

[1] Schultze et al. Science 328, 1658 (2010)

[2] Isinger et al. Science 358 , 893 (2017)

[3] Véniard et al. Phys. Rev. A 54, 721 (1996)

[4] Dahlström et al. Chemical Physics 414, 53 (2013)