Compressed water, ices mixtures and hydrates are overspread on Earth at depth and in the extra-terrestrial space, both interstellar and on outer planets and moons [1-3]. Under the extreme p-T conditions experienced in these icy bodies ices and hydrates display a rich phase diagram, anomalous dynamical and thermal properties, proton conductivity, and enhanced quantum effects [4-8]. Methane and hydrogen hydrates are also expected to be present under very high pressures (10 to 200 GPa) in giant planetary interiors such as Uranus or Neptune. However, the stability of such structures at these pressures is currently debated.
In this talk I will review our recent experimental results - obtained combining neutron and x-ray diffraction, high pressure quasi-elastic neutron scattering , and Raman spectroscopy under high pressure with ab-initio simulations- on water, gas (H2, CH4) filled ices, and hydrates (NH3: H2O) under the extreme conditions experienced in the ice bodies of our solar system [5-12].
Acknowledgments: This work was supported by the Swiss National Science Fund under Grant 200021149487.
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Dr. Jitae Park
Dr. Theresia Heiden-Hecht