Water and ice under extreme conditions
Prof. Dr. Katrin Amann-Winkel (MPI für Polymerforschung Mainz)

Water is ubiquitous and the most important liquid for life on earth. Although the water molecule is seemingly simple, various macroscopic properties of water are most anomalous, such as the density maximum at 4°C or the divergence of the heat capacity upon cooling. Computer-simulations suggest that the anomalous behaviour of ambient and supercooled water could be explained by a two state model of water. An important role in this ongoing debate plays the amorphous forms of water. Since the discovery of two distinct amorphous states of ice with different density (high- and low density amorphous ice, HDA and LDA) it has been discussed whether and how this phenomenon of polyamorphism at high pressures is connected to the occurrence of two distinct liquid phases (HDL and LDL). X-ray free electron laser allow us to investigate metastable states of supercooled water within nano- to microseconds. In my talk I will give an overview on our recent X-ray experiments on supercooled water and amorphous ices.