XAS investigation of the Fe local atomic structure and reactivity in dense Fe-bearing silicate melts

Terrestrial planets and exoplanets are thought to host deep magma oceans at least during their early accretion. The physical (e.g. density and transport properties) and chemical (e.g. redox state of Fe) properties of the dense Fe-bearing silicate melts which compose these magma oceans determine the subsequent evolution of the planet interior and the atmosphere composition. However, experimental DAC studies of silicate liquids are difficult due to the chemical diffusion and ab initio simulations approaches are challenged by the complex chemical behaviour of Fe in oxide melts. This proposal aims at providing insights on Fe-bearing silicates' density and reactivity by measuring the local atomic structure around Fe atoms, and the oxidation and spin states of Fe at pressures relevant for large terrestrial planet interiors. In situ XAS measurements will be performed in shock compressed Fe-bearing silicates on the ID24-ED beamline coupled with the High-Power Laser Facility.