Superionic water at high pressures and temperatures

The aim of this proposal is to explore the structural properties and P-T boundaries of the superionic phases of water, as a continuation of our previous runs HC-2185 and HC-3952. In run HC-2185, using CO2 laser heating, we were able to determine the melting curve of water up to 45 GPa and evidence the transition to the superionic bcc ice [1]. In run HC-3952 we extended the investigated pressure range to 166 GPa using YAG laser heating and observed the bcc-fcc transition at two pressures, 100 and 166 GPa. The aim of the present proposal is to map in more details the bcc-fcc transition line from 50 to 200 GPa and extend the melting line measurement of superionic ice up to 200 GPa. This will allow us to extract the thermodynamics of each phase transition from which it can be determined the molecular or superionic nature.