Time-resolved X-ray absorption spectroscopy to study hematite Fe2O3 and wüstite FeO phase transitions under laser-shock compression

Recent studies of Fe-O phase diagrams have revealed important yet not fully understood phenomena, such as new Fe-O stoichiometries, changes in iron spin and oxidation states, which are important for properly modeling both deep planetary interiors and high-velocity meteorite impacts. The important discrepancies observed between static and dynamic compression phase diagram emphasizes our lack of understanding of the underlying transition mechanisms. X-ray Absorption Spectroscopy (XAS) is particularly well-suited to tackle these questions and explore the interplay between the electronic and atomic structures. In the continuity of our previous experiments at ESRF, we propose Time-Resolved (TR)-XAS at Fe K-edge of laser-shock compressed Fe2O3. Moreover, as FeO has similar transitions but possibly with a different physics, we propose to also investigate this latter thus providing unprecedented knowledge of phase transition mechanisms in iron oxides.