Laboratory soft X-ray setup for transient absorption experiments in the liquid phase using a laser-produced plasma source

With time-resolved soft X-ray spectroscopy, the element-specific dynamics of the electronic structure of disordered systems can be investigated. Measurements of species in dilute liquid solutions are particularly challenging and require high photon flux combined with low experimental noise. This mostly limited these experiments to large-scale facilities, especially for energies above the water window (533 eV). Based on a laser-produced plasma source, our system enables, to the best of our knowledge, the first static and transient experiments in the liquid phase to be performed in the laboratory for energies up to 1400 eV and with a time resolution of 500 ps. We benchmark the system with static investigations of [Ni(CN) 4 ] 2− and transient experiments on the widely used model complex [Fe(bpy) 3 ] 2+ , both in an aqueous solution. The introduced self-referencing concept ensures that the measurements are photon noise limited. Our results form the basis for further liquid-phase experiments investigating the dynamics in diluted solutions.