Ab initiostudy of the optical properties of shocked LiF

The equation of state and optical properties of shocked LiF are investigated using quantum molecular dynamics (QMD) in a wide range of pressures and temperatures along the principal Hugoniot. These simulations are bridging the gap between shock experiments up to 2 Mbars and recent laser shock experiments beyond 6 Mbars. We find that the melting of LiF corresponds to an increase in absorption which is later followed by an increase in reflectivity. The reflectivities computed at high pressures are in close agreement with the experimental measurements but with Hugoniot conditions at much lower temperatures and pressures than measured experimentally. Finally, we provide a simple fit to the variation of the QMD index of refraction for pressures above 1.5 Mbars.