Water is the most important liquid for life on Earth. Although a water molecule is apparently simple, the hydrogen-bonded network keeping these molecules together and determining the many anomalous macroscopic properties of water, is still a puzzle. Among different scenarios proposed to explain the anomalies in water, the most controversial issue is the hypothetical existence of two distinct liquid states: high- and low-density liquid (HDL, LDL). At ambient conditions the two structural components making up the two liquids fluctuate and cannot be studied as separate states. Rapid cooling of liquid water forms a low-density amorphous ice (LDA). High-density amorphous ice (HDA) can be made instead by pressure-induced amorphization of crystalline ice. A fascinating question arises: are the two amorphous ices the counterparts of the two proposed liquids states?
Modern X-ray scattering methods provide powerful tools to investigate both static structure and structural dynamics on different length- and timescales. Using X-rays, we have recently shown the diffusive character of HDL and LDL around their proposed glass transition temperatures at ambient pressure, but studies at elevated pressures are missing and challenging. This project aims to develop new experimental in situ pathways to study the pressure dependence of the hypothesized glass-to-liquid transition in amorphous ices. The experiments will have a high impact on the debate about different models explaining water´s mysteries.