Ion solvation structure and dynamical information via deviations from the solvent-berg diffusion model

We present a simple separation of ion diffusion into solvent-berg and non-solvent-berg components. The non-solvent-berg component is shown to contain relevant information concerning solvent structure and dynamics and correlates reasonably well with 1st shell water residence times for 2+ and 3+ charged cations; no such dependence is detected for −1 and +1 charged ions. An empirical equation is proposed for estimating 1st shell water residence times of +2 and +3 cations. We suggest the non-solvent-berg component as a proxy for the formation of an extended solvation region. This work thus provides a new approach to investigate solvent dynamics.