Pulse dependence of prevalent pathways in xenon driven by an x-ray free-electron-laser pulse

TL;DR

This study investigates how the duration of x-ray free-electron-laser pulses influences the ionization pathways and yields of xenon atoms, revealing that longer pulses enhance highly-charged ion production through Auger cascades.

Contribution

It introduces a Monte-Carlo simulation approach for xenon ionization under FEL pulses, analyzing pathway dependence on pulse duration and comparing with experimental data.

Findings

Longer pulses increase yields of highly-charged xenon ions.

Dominant ionization pathways depend on pulse duration.

Auger cascades significantly contribute to high charge states.

Abstract

We study the interaction of xenon with an 850 eV photon energy FEL pulse. We do so by employing a Monte-Carlo technique. We compute the single-photon ionisation cross sections and Auger rates, used in the Monte-Carlo technique, by adopting to atoms a formalism we previously developed for diatomic molecules. We determine the yields of the ion states of driven xenon and compare with previously obtained experimental results. To better understand the yields obtained, we identify the prevalent pathways leading to the formation of each final ion state of xenon. We gain further insight into the high yields of highly-charged ion states by comparing the yields and dominant pathways of these ion states of xenon when driven by different FEL pulses that have the same energy. We show that higher-charged ion states have higher yields when xenon is driven by longer-duration pulses due to Auger cascades taking place between subsequent single-photon ionisations.