5. Theoretical Physics (CSN4)

Ultrafast Time-resolved X-ray Absorption Spectroscopy

by Dr Frederico Lima (EPFL, Losanna)

Aula Bruno Touschek (LNF)

Aula Bruno Touschek


Via Enrico Fermi, 40 00044 Frascati (Roma)
Over the past ten years, there have been huge efforts directed towards investigating ultrafast photoinduced structural changes in molecules, crystals, materials and proteins in a pump-probe scheme. The goal is to retrieve the structural dynamics of the systems on the atomic scales of space (sub-A) and time (femtoseconds to picoseconds). The chemical selectivity of X-ray Absorption Spectroscopy (XAS) on a laser pump/X-ray probe scheme allows the retrieval of not only the local transient geometric structure of the system under study, but also the underlying electronic structure changes that drive the structural dynamics. On this talk, as well as presenting a fast overview of the time-resolved XAS experiments, I will show some results of the structural studies of the ultrafast dynamics of a spin-crossover model system on the picosecond and femtosecond time scale. I will also present some new results on the photo-detachment of diatomic ligands of Myoglobin in physiological media. The recently implemented scheme of high-reperition rate measurements allow the recording of high quality data and also dilute systems, as the case of proteins in solution.