Studies of water thermodynamics have long been tied to the identification of two distinct families of local structures, whose competition could explain the origin of the many thermodynamic anomalies and the hypothesized liquid-liquid critical point in water. Despite the many successes and insights gained, the structural indicators proposed throughout the years were not able to unequivocally identify these two families over a wide range of conditions. We show that a recently introduced indicator, psi, which exploits information on the hydrogen bond network connectivity, can reliably identify these two distinct local environments over a wide range of thermodynamic conditions (188-300 K and 0-13 kbar) and that close to the liquid-liquid critical point, the spatial correlations of density fluctuations are identical to those of the psi indicator. Our results strongly support the idea that water thermodynamic properties arise from the competition between two distinct and identifiable local environments.

Identification of local structures in water from supercooled to ambient conditions / Foffi, Riccardo; Sciortino, Francesco. - In: THE JOURNAL OF CHEMICAL PHYSICS. - ISSN 0021-9606. - 160:9(2024). [10.1063/5.0188764]

Identification of local structures in water from supercooled to ambient conditions

Foffi, Riccardo;Sciortino, Francesco
2024

Abstract

Studies of water thermodynamics have long been tied to the identification of two distinct families of local structures, whose competition could explain the origin of the many thermodynamic anomalies and the hypothesized liquid-liquid critical point in water. Despite the many successes and insights gained, the structural indicators proposed throughout the years were not able to unequivocally identify these two families over a wide range of conditions. We show that a recently introduced indicator, psi, which exploits information on the hydrogen bond network connectivity, can reliably identify these two distinct local environments over a wide range of thermodynamic conditions (188-300 K and 0-13 kbar) and that close to the liquid-liquid critical point, the spatial correlations of density fluctuations are identical to those of the psi indicator. Our results strongly support the idea that water thermodynamic properties arise from the competition between two distinct and identifiable local environments.
2024
liquid-liquid transition, rsupercooled water, structural indicators
01 Pubblicazione su rivista::01a Articolo in rivista
Identification of local structures in water from supercooled to ambient conditions / Foffi, Riccardo; Sciortino, Francesco. - In: THE JOURNAL OF CHEMICAL PHYSICS. - ISSN 0021-9606. - 160:9(2024). [10.1063/5.0188764]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1722811
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