Single-Ion Hydration Through the Lens of Data-Driven Many-Body Potentials

Single-ion hydration provides a stringent test of molecular models because local ion–water interactions, collective polarization, nuclear quantum effects, and long-range electrostatics all contribute to experimentally measurable structure, spectra, and thermodynamics. Here we discuss how data-driven many-body potentials, in particular MB-pol for water and MB-nrg for hydrated ions, provide a physically transparent route from correlated electronic structure data to predictive simulations of ion hydration from clusters to bulk water and aqueous interfaces. We emphasize how this framework transforms single-ion hydration from a parametrization problem into a hierarchy of many-body observables, and we outline opportunities for connecting simulations directly with interfacial spectroscopy, hydration free energies, and complex electrolyte environments.