An Open Window on Ultrafast X-ray Spectroscopy

Ultrafast X-ray spectroscopy enables the exploration of molecular dynamics with unprecedented temporal resolution, element specificity, and site selectivity. These unique properties make it ideal for studying intra- and intermolecular interactions in the liquid phase.

In this study, researchers highlight major experimental advances, such as water photolysis (light-induced decomposition) and proton transfer on femtosecond (10⁻¹⁵ second) and attosecond (10⁻¹⁸ second) timescales, the dynamics of free electrons in solution, charge transfer processes in metal complexes, multiscale dynamics of heme proteins, and extreme ultraviolet harmonic spectroscopy in the liquid phase.

“Access to what is known as the ‘water window’ (between 200 eV and 550 eV) through new high-brightness ultrafast radiation sources, allowing the study of essential elements of organic and biological chemistry (Carbon, Nitrogen, Oxygen), is a key breakthrough in this field,” emphasizes Professor Jean-Pierre Wolf from the Department of Applied Physics at the University of Geneva.

These advances have improved temporal resolution by up to a factor of 1000, opening a new field of purely electronic dynamics where nuclei remain stationary within molecules. This allows the separation of electronic and structural dynamic effects at a fundamental level. Ultrafast X-ray spectroscopy thus provides a decisive advantage over UV and visible spectroscopies by facilitating the interpretation of observed phenomena and enabling the study of complex systems with unprecedented precision.