Generalized atomic processes for interaction of intense femtosecond XUV- and X-ray radiation with solids

Generalized atomic processes are proposed to establish a consistent description from the free-atom approach to the heated and even up to the cold solid. It is based on a rigorous introduction of the Fermi-Dirac statistics, Pauli blocking factors and on the respect of the principle of detailed balance via the introduction of direct and inverse processes. A probability formalism driven by the degeneracy of the free electrons enables to establish a link of atomic rates valid from the heated atom up to the cold solid. This allows to describe photoionization processes in atomic population kinetics and subsequent solid matter heating on a femtosecond time scale. The Auger effect is linked to the 3-body recombination via a generalized 3-body recombination that is identified as a key mechanism, along with the collisional ionization, that follows energy deposition by photoionization of inner shells when short, intense and high-energy radiation interacts with matter. Detailed simulations are carried out for aluminum that highlight the importance of the generalized approach

Simulation of XFEL induced fluorescence spectra of hollow ions and studies of dense plasma effects

International audienc

A superconfiguration approach to multi-electron ionization of Xe under strong x-ray irradiation.

The production of highly ionized states in xenon under intense x-ray irradiation, is discussed with the help of specific calculations. The approach, which retains only one-photon absorption processes (photoionization and photoexcitation) as well as Auger and radiative relaxations, makes use of properly defined superconfigurations as a global ensemble of configurations. With a tractable number of (super)levels, we explain the occurrence of the highest charge states observed in experiments