Probing solid-solid and solid-liquid phase transitions in laser-shocked Ni by means of time resolved XAS

The phase diagram and melting curve of Ni under dynamic loading conditions are still poorly known, and the scarce available data show large disagreement with the existing static high pressure data and microscopic theoretical calculations. In this proposal, we will therefore investigate the solid-solid and solid-liquid transitions in shock compressed Ni, by coupling time resolved XAS measurements with laser shock compression performed using the ID24’s High Power Laser Facility (HPLF). These EXAFS/XANES measurements will provide information on the local-structure that cannot be determined through X-ray diffraction (XRD) measurements, and they will be directly compared to static XAS data previously measured on ID24 and to extensive ab initio MD simulations.