Structural study of laser shocked MgO using X-rays Absorption Near Edge Spectroscopy

MgO is one of the components of rocky materials, constituting the Earth's 

and terrestrial planets mantles. Detailed description of his phase diagram 

is essential to properly model interior structures and dynamics of these 

planets [1]. We report first time-resolved X-ray absorption near edge 

spectroscopy (XANES) investigation of warm dense MgO at multi Mbar 

pressures. The results were obtained on the LULI 2000 at the Ecole 

Polytechnique using a nanosecond beam to compress a sandwiched CH/MgO/C/CH 

target and the picosecond beam to generate the X-ray source. With an 

approach previously validated on Al, we obtained XANES data at a wide range 

of temperature and density conditions. With the support of quantum molecular 

dynamic simulations we show the MgO band gap closure mechanism and the local 

structural properties of liquid MgO.