Quantum-state-resolved X-ray multiphoton ionization dynamics

Sang-Kil Son, Thomas M. Baumann, Sebastian Cardoch, Nicuşor Tîmneanu, Michael Meyer, Robin Santra, and Jan-Erik Rubensson

[BibTeX]

Intense XFEL pulses can induce multiple sequences of inner-shell ionization events and accompanying decay processes in atoms, producing highly-charged ions. In general, X-ray multiphoton ionization dynamics have been so far described in terms of time-dependent populations of the electronic configurations visited during the ionization dynamics, neglecting individual state-to-state transition rates and energies. We extend our XATOM toolkit to study state-resolved dynamics based on time-dependent quantum-state populations, by combining a state-resolved electronic-structure method based on first-order many-body perturbation theory with a Monte Carlo rate-equation method. Here we present a recent study of quantum-state-resolved X-ray multiphoton ionization dynamics of neon gas interacting with intense X-ray pulses generated by European XFEL. Several unexpected resonance features, for examples, multi-resonant inelastic X-ray scattering (MRIXS), emergence of pseudo-resonance and resonance-mediated double-core-hole (DCH) formation, are identified with state-resolved ionization-dynamics calculations in the isolated-atom limit. At the same time, collision-driven processes and plasma explosion are investigated in the plasma limit, suggesting measured time-resolved X-ray emission spectra (tr-XES) as real-time observation of X-ray-created explosion dynamics.

Tags: x-ray multiphoton ionization, state-resolved, ionization dynamics, XATOM, CFEL, DESY