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Pure Appl. Chem., 2013, Vol. 85, No. 1, pp. 237-246

Published online 2012-07-01

Lanthanoids(III) and actinoids(III) in water: Diffusion coefficients and hydration enthalpies from polarizable molecular dynamics simulations

Fausto Martelli1, Sacha Abadie1, Jean-Pierre Simonin2, Rodolphe Vuilleumier3 and Riccardo Spezia1*

1 Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, UMR 8587 CNRS-CEA-UEVE, Université d’Evry Val d’Essonne, Evry, France
2 Laboratoire PECSA (UMR CNRS 7195), Université P.M. Curie, Paris, France
3 Ecole Normale Supérieure, Département de Chimie, Paris, France, and UPMC Université Paris 06, UMR 8640 CNRS-ENS-UPMC, Paris, France

Abstract: By using polarizable molecular dynamics (MD) simulations of lanthanoid(III) and actinoid(III) ions in water, we obtained ionic diffusion coefficients and hydration enthalpies for both series. These values are in good agreement with experiments. Simulations thus allow us to relate them to microscopic structure. In particular, across the series the diffusion coefficients decrease, reflecting the increase of ion–water interaction. Hydration enthalpies also show that interactions increase from light to heavy ions in agreement with experiment. The apparent contradictory result of the decrease of the diffusion coefficient with decreasing ionic radius is tentatively explained in terms of dielectric friction predominance on Stokes’ diffusive regime.