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

YZ Song and XF Wu, JOURNAL OF CHEMICAL PHYSICS, 162, 114508 (2025).

DOI: 10.1063/5.0247114

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 epsilon 0 with increasing pressure, a trend that is qualitatively consistent with experimental observations. This increase in epsilon 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 epsilon 0, our results reveal a decrease in the Kirkwood correlation factor GK with increasing pressure. This decrease in GK 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.

Return to Publications page