A group of scientists from Germany, Austria and Sweden determined that room temperature water consists of two liquids that differ in viscosity and density. During rapid cooling, both components become two forms of amorphous ice.
In earlier studies, models showing the behavior of water molecules demonstrated that hydrogen oxide can have two liquid states that can transform into each other. This hypothesis was confirmed by the fact that amorphous ice, characterized by a random arrangement of molecules, is capable of taking forms with high (HDA) and low (LDA) density.
To study these structural changes, the scientists used X-ray spectroscopy, which is based on small-angle (SAXS) and wide-angle (WAXS) X-ray scattering. Experts have found that high-energy photons, interacting with water molecules, are deflected at appropriate angles. With the help of WAXS they determined the density of molecules, and SAXS - the dynamics.
As a result, it turned out that more than 110 degrees Kelvin (-163 degrees Celsius) provoke the transition of dense amorphous ice into a dense liquid (HDL). Further heating gives the second, less dense form (LDL), but the transition rate at 130 Kelvin is reduced. In this regard, scientists have come to the conclusion that room temperature water consists of two liquids.
Victoria Romanova