X-ray absorption near edge spectroscopy study of MgO in the Warm Dense Matter regime
Date | Mo, 16.07.2018 | |
Time | 16:45 | |
Speaker | Dr. Riccardo Bolis, CNRS, PIMM Laboratory, ENSAM Paris | |
Location | ETH Hönggerberg, HPF G6 | |
Program | Abstract: MgO is a building block of the major constituents of mantles in terrestrial planets. Knowledge of the electronic properties of planetary components in the liquid phase is crucial for the comprehension of electromagnetic mantle-core coupling, convection patterns and planetary magnetic fields. X-ray absorption near edge spectroscopy (XANES) has been coupled with laser driven shock compression to study structural and electronic properties of MgO at planetary relevant conditions. A high power nanosecond laser beam has been used to drive a strong uniform shock wave in the sample and a picosecond pulse has been used to generate a spectrally flat broadband x-ray source near the Mg K edge. This method allowed to obtain XANES spectra across a large region of the phase diagram spanning density up to 5.5 g/cc and temperatures up to 30 000 K. With the support of quantum molecular dynamic simulations, the MgO band gap closure mechanism and the local structural properties of liquid MgO at planetary relevant conditions have been unveiled. |
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Link | Opteth | |
Weizmann |