Desolvation of metal cations at the mineral-water interface is a necessary precursor to the incorporation of those ions into the crystal lattice of mineral precipitates. Molecular dynamics simulations indicate that desolvation rates (i.e., water exchange rates; kwex) of isotopes of Li+, K+, Rb+, Ca2+, Sr2+, and Ba2+ all follow an inverse power-law dependence on cation mass (kwex ? m-?). The value of the mass exponent ? is observed to be invariant within error for all elements at a given temperature; these results are corroborated by Reaction Rate Theory calculations. In all isotopic systems investigated, the simulation-derived mass-dependences predict enrichment of the light isotope in precipitating solids relative to the surrounding fluid, consistent with that observed in natural materials.

Isotopic mass dependence of cation desolvation rates in aqueous solution

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.