Ion Solvation at Thermodynamic Extremes from First Principles*

The properties of aqueous salt solutions at high pressure and temperature are crucial to understanding geochemically relevant fluids. We report on the properties of aqueous monovalent ions at high pressure and temperature (1 GPa/1000 K, 11 GPa/1000 K), as obtained from first-principles molecular dynamics simulations [1]. In particular, we discuss the effect of ions on the structure and diffusion of water and the effect of water dissociation occurring under pressure, on ion solvation. We further analyze vibrational signatures of solvated ions, by comparing computed infrared and Raman spectra of salty and pure water [2] at the same conditions. Finally we present results for ionic conductivity and dielectric constants.

[1] http://qboxcode.org
[2] V. Rozsa, D. Pan, F. Giberti, and G. Galli, Proc. Natl. Acad. Sci. USA, 201800123, (2018).