Rostock 2019 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 26: Atomic systems in external fields

A 26.1: Poster

Mittwoch, 13. März 2019, 16:15–18:15, S Fobau Physik

Influence of nuclear motion on two-center photoionization — •Fiona Grüll, Alexander B. Voitkiv, and Carsten Müller — Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, Deutschland

Photoionization of an atom A can be strongly enhanced in the presence of a neighboring atom B due to two-center electron correlations. For certain resonant photon energies, atom B can first be excited and afterwards transfer the excitation energy radiationlessly via dipole-dipole interactions to atom A, leading to its ionization. This indirect ionization pathway can dominate over the direct photoionization by several orders of magnitude, as was predicted some years ago assuming a fixed internuclear distance [1]. A related experiment observed enhanced photoionization in heteroatomic dimers, though at substantially reduced scale [2]. In light of this, we analytically study how two-center photoionization is influenced by the nuclear motion in a molecule when considering Li-He dimers as an example. Shifts of the atomic energy levels in the presence of a neighboring atom are calculated as a function of the internuclear distance. Besides, the internuclear motion is accounted for by considering the relevant vibrational states in the molecule.
[1] B. Najjari, A. B. Voitkiv and C. Müller, Phys. Rev. Lett. 105, 153002 (2010)
F. Trinter et al., Phys. Rev. Lett. 111, 233004 (2013)