Resonant inelastic x-ray scattering in warm-dense Fe compounds beyond the SASE FEL resolution limit

• DOI: 10.48550/arxiv.2402.00039
• Publication Date: 2024-01-11
• Authors: Alessandro Forte; Thomas Gawne; Karim K. Alaa El-Din; Oliver Humphries; Thomas R. Preston; Céline Crépisson; Thomas F. Campbell; Pontus Svensson; Sam Azadi; P. G. Heighway; Yuanfeng Shi; D. A. Chin; Ethan Smith; Carsten Baehtz; V. Bouffetier; Hauke Höppner; D. McGonegle; M. Harmand; Gilbert Collins; J. S. Wark; D. N. Polsin; S. M. Vinko

Resonant inelastic x-ray scattering (RIXS) is a widely used spectroscopic technique, providing access to the electronic structure and dynamics of atoms, molecules, solids. However, RIXS requires narrow bandwidth probe achieve high spectral resolution. The challenges in delivering an energetic monochromated beam from free electron laser (XFEL) thus limit its use few-shot experiments, including for study energy density systems. Here we demonstrate that by correlating measurements self-amplified spontaneous emission (SASE) spectrum XFEL with signal, using dynamic kernel deconvolution neural surrogate, can resolutions substantially higher than those normally afforded incoming beam. We further show how this technique allows us discriminate between valence structures Fe Fe$_2$O$_3$, provides temperature as well M-shell binding energies estimates warm-dense compounds.