Pressure Effects on Water Dynamics by Time-Resolved Optical Kerr Effect

Year: 2020

Authors: Taschin A., Bartolini P., Fanetti S., Lapini A., Citroni M., Righini R., Bini R., Torre R.

Autors Affiliation: Univ Firenze, European Lab Nonlinear Spect LENS, I-50019 Florence, Italy; CNR, ICCOM, Ist Chim Composti OrganoMetall, Florence, Italy; Ist Nazl Ric Metrol, INRIM, I-10135 Turin, Italy; Univ Firenze, Dipartimento Chim Ugo Schiff, I-50019 Florence, Italy; Univ Firenze, Dipartimento Fis & Astron, I-50019 Florence, Italy.

Abstract: Despite water being the most common and most widely studied substance in the world, it still presents unknown aspects. In particular, water shows several thermodynamic and dynamical anomalies in the liquid and supercooled metastable phases, and the natures of these phases are still hotly debated. Here, we report measurements of water using the optical Kerr effect as a function of pressure along two isotherms, at 273 K from 0.1 to 750 MPa and at 297 K from 0.1 to 1350 MPa, reaching the supercooled metastable phase. The structural relaxation and the low frequency vibrational dynamics of water show a peculiar pressure dependence similar to that of other dynamical properties. The data analysis suggests the presence in the water phase diagram of a crossover area that divides two regions characterized by different dynamic regimes, which appear to be related to two liquid forms, one dominated by the high density water and the other by the low density water.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Volume: 11 (8)      Pages from: 3063  to: 3068

More Information: This research was funded by Ente Cassa di Risparmio – Firenze (2016-0866), Ministero dell’Istruzione dell’Universita e della Ricerca – Italia (PRIN2017-2017Z55KCW), and European Community by Laserlab-Europe (H2020 EC-GA-654148). We acknowledge M. De Pas, A. Montori, and M. Giuntini for providing their continuous assistance in the setup of the electronics and R. Ballerini and A. Hajeb for the accurate mechanical realizations.
KeyWords: Low-frequency Spectrum; Supercooled Water; Liquid Water; Self-diffusion; Dependence; Relaxation; Anomalies; Density; H2o
DOI: 10.1021/acs.jpclett.0c00363

Citations: 9
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