Relativistic effects in x-ray multiphoton ionization dynamics

Sang-Kil Son

[BibTeX][slide: 12Mb]https://www.rehe2020.it

X-ray Free-Electron Lasers (XFELs) have brought an impact on various scientific areas across physics, chemistry, materials science, and life science. When an atom or a molecule is exposed to an intense x-ray pulse that is generated by XFEL, it is ionized to a highly charged ion via a sequence of single-photon ionization and accompanying relaxation processes. Understanding of this x-ray multiphoton ionization dynamics is crucial for most XFEL applications. To this end, we have developed the dedicated toolkits to investigate x-ray-induced processes and to simulate ionization dynamics. If x-ray multiphoton ionization involves deep inner-shell electrons in heavy atoms, energy shifts by relativistic effects play an important role in ionization dynamics [1,2]. In this talk, we will present recent XFEL studies of atomic and molecular systems containing heavy atoms irradiated by intense XFEL pulses [1–5]. In particular, we will demonstrate how the relativistic effects are exhibited in x-ray multiphoton ionization dynamics of xenon atoms [1,2], in combination with resonances of highly charged ions that are initially hidden in neutral xenon atoms [1–3]. In molecular cases [4,5] we did not take relativistic effects into account, but this remains a challenge for the future. [1] K. Toyota, S.-K. Son, and R. Santra, Phys. Rev. A (2017), 95, 043412; [2] B. Rudek et al., Nat. Commun. (2018), 9, 4200; [3] S.-K. Son, R. Boll, and R. Santra, Phys. Rev. Res. (2020), 2, 023053; [4] X. Li et al., Phys. Rev. Lett. (2021), 127, 093202; [5] R. Boll et al., Nat. Phys. (2022), 18, 423.

Tags: relativity, x-ray multiphoton ionization, Xe, CH3I, iodopyridine, XATOM, XMOLECULE, XMDYN, XFEL, CFEL, DESY

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