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arXiv · 2601.18318

Structural and dynamic anomalous properties of TIP4P/2005 water at extreme pressures

José Martín-Roca·Alberto Zaragoza·Frédéric Caupin·Chantal Valeriani
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Abstract

Water shows numerous thermodynamic, dynamic, and structural anomalies. Recent experiments [Eichler et al. Phys. Rev. Lett. 134, 134101 (2025)], based on measurements of shear and bulk viscosities of liquid water up to 1.6 GPa, have reported the existence of a minimum in the variation of the structural relaxation time {\tau}{\alpha} with pressure at room temperature. Here we investigate this and related properties with molecular dynamics simulations of the TIP4P/2005 water model, performed at extreme pressures commensurate with the experiments. Specifically, we compute dynamic (self-diffusion, shear and bulk viscosities, and structural relaxation time) and structural (oxygen-oxygen radial distribution function and structure factor, translational order parameter) properties down to 220 K and up to 2.7 GPa. We find good agreement with the experimental observations, and confirm the existence of a minimum in {\tau}{\alpha} . The microscopic information obtained from the simulations suggests that this anomaly is connected with the sudden reorganization of the hydrogen bond network induced by pressurization.

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José Martín-Roca, Alberto Zaragoza, Frédéric Caupin, Chantal Valeriani. 2026-01-26. Structural and dynamic anomalous properties of TIP4P/2005 water at extreme pressures. https://arxiv.org/abs/2601.18318

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