Pablo G. Debenedetti is the Class of 1950 Professor in Engineering and Applied Science, Professor of Chemical and Biological Engineering, and Dean for Research. He served as vice dean of Princeton’s School of Engineering and Applied Science from 2008 to 2013 and chair of the chemical engineering department between 1996 and 2004. Debenedetti obtained his B.S. degree in chemical engineering from Buenos Aires University, Argentina (1978), and his M.S. (1981) and Ph.D. (1985) degrees, also in chemical engineering, from the Massachusetts Institute of Technology. He joined the faculty of Princeton University in 1985. Debenedetti uses theoretical and computational tools to study the properties of water and aqueous systems, and their applications in areas ranging from the long-term preservation of biomolecules and pharmaceutical compounds to water desalination. His interests span the thermodynamics and statistical mechanics of liquids and glasses, as well as explorations of water and aqueous solutions, protein thermodynamics, nucleation, metastability, and the origin of homochirality in biological systems. Using theoretical and computational methods, Debenedetti and his students have provided key insights into the physical properties of cold liquid water (supercooled water), which is found in large quantities in high-altitude clouds. Debenedetti is the author of one book, Metastable Liquids, and more than 300 scientific articles. His professional honors include the Presidential Young Investigator Award from the National Science Foundation (1987); the Camille and Henry Dreyfus Teacher-Scholar Award from the Dreyfus Foundation (1989); a Guggenheim Memorial Foundation Fellowship (1991); the Professional Progress (1997), Walker (2008) and Institute Lecturer (2013) awards from the American Institute of Chemical Engineers; the John M. Prausnitz Award in Applied Chemical Thermodynamics (2001); the Joel Henry Hildebrand Award in the Theoretical and Experimental Chemistry of Liquids from the American Chemical Society (2008); and the Guggenheim Medal from the Institution of Chemical Engineers (2017). He is a member of the National Academy of Engineering, the American Academy of Arts and Sciences, and the National Academy of Sciences, and a Fellow of the American Institute of Chemical Engineers, the American Association for the Advancement of Science, and the American Physical Society. ABSTRACT: Water plays a central role in the physical and chemical processes that sustain life as we know it. Its ubiquity and importance notwithstanding, there remain major open questions concerning the microscopic origin and thermodynamic consequences of water’s physical properties, which are anomalous by comparison to those of most other liquids. Water’s oddities become more pronounced at low temperatures, especially in the supercooled regime, where the liquid is metastable with respect to crystallization. The existence of a first-order phase transition between two liquid forms of water, terminating at a critical point under deeply supercooled conditions, has been proposed as a thermodynamically consistent way of interpreting experimental observations (Mishima and Stanley, Nature, 396, 329, 1998). I will present recent computational results on metastable criticality in realistic models of water (Debenedetti et al., Science, 369, 289, 2020), supercooled water thermodynamics probed with an ab-initio deep neural network model (Gartner et al., PNAS, 117, 26040, 2020), and the relationship between the long-range structure of water glasses and criticality (Gartner et al., Nature Communications, 12, 3398, 2021). These studies are consistent with the existence of a second, metastable critical point in water. All are welcome to attend this online event which will also be livestreamed from the ICTP website. Register in advance for this webinar: https://zoom.us/webinar/register/WN_kXFGJGfLRXiS3kmnkshAKw After registering, you will receive a confirmation email containing information about joining the webinar.