Pressure-induced structural and dielectric changes in liquid water at room temperature

Song, Yizhi [Temple University, Philadelphia, PA (United States)] (ORCID:0000000330502581); Wu, Xifan [Temple University, Philadelphia, PA (United States)] (ORCID:0000000165618942)

doi:10.1063/5.0247114

DOE OSTI · 2589823

Pressure-induced structural and dielectric changes in liquid water at room temperature

Song, Yizhi [Temple University, Philadelphia, PA (United States)] (ORCID:0000000330502581)·Wu, Xifan [Temple University, Philadelphia, PA (United States)] (ORCID:0000000165618942)

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Abstract

Understanding the pressure-dependent dielectric properties of water is crucial for a wide range of scientific and practical applications. In this study, we employ a deep neural network trained on density functional theory data to investigate the dielectric properties of liquid water at room temperature across a pressure range of 0.1–1000 MPa. We observe a nonlinear increase in the static dielectric constant ɛ 0 with increasing pressure, a trend that is qualitatively consistent with experimental observations. This increase in ɛ 0 is primarily attributed to the increase in water density under compression, which enhances collective dipole fluctuations within the hydrogen-bonding network as well as the dielectric response. Despite the increase in ɛ 0 , our results reveal a decrease in the Kirkwood correlation factor G K with increasing pressure. Furthermore, this decrease in G K is attributed to pressure-induced structural distortions in the hydrogen-bonding network, which weaken dipolar correlations by disrupting the ideal tetrahedral arrangement of water molecules.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS Density functional theory Dielectric properties Machine learning Molecular dipole moments Molecular dynamics

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Song, Yizhi [Temple University, Philadelphia, PA (United States)] (ORCID:0000000330502581), Wu, Xifan [Temple University, Philadelphia, PA (United States)] (ORCID:0000000165618942). 2025-03-21. Pressure-induced structural and dielectric changes in liquid water at room temperature. https://doi.org/10.1063/5.0247114

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