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arXiv · 2502.09915

Pressure-Induced Structural and Dielectric Changes in Liquid Water at Room Temperature

Yizhi Song·Xifan Wu
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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 MPa to 1000 MPa. We observe a nonlinear increase in the static dielectric constant $ε_0$ with increasing pressure, a trend that is qualitatively consistent with experimental observations. This increase in $ε_0$ 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 $ε_0$, our results reveal a decrease in the Kirkwood correlation factor $G_K$ with increasing pressure. 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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Yizhi Song, Xifan Wu. 2025-02-14. Pressure-Induced Structural and Dielectric Changes in Liquid Water at Room Temperature. https://doi.org/10.1063/5.0247114

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