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

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 τα 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, structure factor, and 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 τα. The microscopic information obtained from the simulations suggests that this anomaly is related to the sudden reorganization of the hydrogen bond network induced by pressurization.