Strong-field photoionization in two-center atomic systems

Abstract

Photoionization of an atom A by a strong laser field in the presence of a spatially well-separated neighboring atom B is considered. The laser field frequency is assumed to lie below the ionization potential of atom A and be resonant with a dipole-allowed transition in atom B. In this situation, the ionization may occur either directly by multiphoton absorption from the laser field at the first atomic center. Or via an indirect pathway involving two-center electron-electron correlations, where the neighbor atom B is first photoexcited and, afterwards, transfers its energy upon deexcitation radiationlessly to atom A. Considering monochromatic as well as bichromatic laser fields, we study various coupling regimes of the photoionization process and identify experimentally accessible parameter domains where the two-center channel is dominant.

Interatomic and Intermolecular Coulombic Decay

“…A peculiarity, however, is strong field ionization. To our knowledge, there has been, despite theoretical work on the topic (with respect to loosely bound matter), , no experimental observation of ICD in this research field (see, e.g., refs and for work on argon dimers). The intensity needed to generate states decaying by ICD in loosely bound matter by strong fs-lasers is typically very high.…”

Influence of nuclear motion on resonant two-center photoionization

“…As specific example, a diatomic system of Li and He was considered [12]. Related theoretical studies (see also [13]) have treated two-center single-photon double ionization [14], strong-field multiphoton ionization [15] and electron-impact ionization [16] in heteroatomic systems as well as two-photon single-ionization in homoatomic systems [17].…”