Speaker
Description
Water is a key-ingredient for life as we know it and plays a central role in maintaining Earth’s climate within the limits that life can tolerate. Water is all around us, yet its properties are radically different from essentially all other substances. The density maximum at 4 degrees, that makes ice cubes float in our drinking glasses, is the most famous example among water’s anomalous properties. Thermodynamic response functions including isothermal compressibility and heat capacity at constant pressure are related to fluctuations in volume and entropy, respectively. These fluctuations increase upon cooling of ambient water and diverge in the supercooled regime.[1] An accumulating number of studies, both simulations[2] and experiments[3], show that the origin of these non-thermal fluctuations is a transition between two distinct forms of liquid water (a high- and a low-density liquid) and the existence of a liquid-liquid critical point.[4] The consequences of this bimodality are not limited to the supercooled regime but also affect the properties of ambient water in our drinking glasses and even the water in our cells. In my presentation I will explain how we use polarizable atom interaction neural networks to explore these fascinating phenomena and search for the structural motifs responsible for water’s unique properties. Is there hidden structure in ambient water?
References
1. P. Gallo et al., ”Water: A Tale of Two Liquids”, Chem. Rev. 2016, 116, 13, 7463-7500.
2. J. C. Palmer et al., ”Advances in Computational Studies of the Liquid–Liquid Transition in Water and Water-Like Models”, Chem. Rev. 2018, 118, 18, 9129-9151.
3. K. H. Kim et al., ”Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure”, Science, 2020, 370, 978-982.
4. S. You et al., ”Experimental evidence of a liquid-liquid critical point in supercooled water”, Science, 2026, 391, 1387-1391.