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 [1] 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 [2] with a Monte Carlo rate-equation method [3]. This allows us to explore spectroscopic detail in XFEL experiments that have been limited with electronic configuration or super-configuration approaches. Here we present a recent study of state-resolved X-ray multiphoton ionization dynamics of neon gas interacting with intense X-ray pulses generated by European XFEL. Many unexpected resonance features are identified with quantum-state-resolved ionization-dynamics calculations in the isolated-atom limit. X-ray-driven formation of hot electron plasma and its non-equilibrium evolution dynamics are investigated in the plasma limit. Our study of quantum-state-resolved X-ray multiphoton ionization dynamics opens up new opportunities for high-resolution high-intensity X-ray spectroscopy. — [1] XATOM in XRAYPAC: https://gitlab.desy.de/CDT/xraypac. [2] L. Budewig, S.-K. Son, and R. Santra, Phys. Rev. A 105, 033111 (2022). [3] L. Budewig, S.-K. Son, and R. Santra, Phys. Rev. A 107, 013102 (2023).

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