Acetylacetone photodynamics at a seeded free-electron laser

Electron and ion spectra of acetylacetone have been measured after pumping at 261 nm and probing with the FERMI monochromatic beam at 19.23 eV, up to a total pump-probe delay of 200 picoseconds. The negligible photon energy jitter at FERMI and the resulting high energy resolution, together with the high intensity, provide electron spectra with unprecedented quality, allowing us to monitor the time evolution of the photoexcited species through several well-characterized steps. The ultrafast photodynamics of acetylacetone has been elucidated in great detail with the aid of state-of-the-art static and dynamics calculations. Similarities and contradictions with previous data sets are underlined.