@article {90, title = {Structure and transport of aqueous electrolytes: From simple halides to radionuclide ions}, journal = {Journal of Chemical Physics}, volume = {141}, year = {2014}, month = {Sept-28-2014}, pages = {124508}, type = {Article}, abstract = {

Molecular simulations are used to compare the structure and dynamics of conventional and radioactive aqueous electrolytes: chloride solutions with sodium, potassium, cesium, calcium, and strontium. The study of Cs+ and Sr2+ is important because these radioactive ions can be extremely harmful and are often confused by living organisms for K+ and Ca2+, respectively. Na+, Ca2+, and Sr2+ are strongly bonded to their hydration shell because of their large charge density. We find that the water molecules in the first hydration shell around Na+ form hydrogen bonds between each other, whereas molecules in the first hydration shell around Ca2+ and Sr2+ predominantly form hydrogen bonds with water molecules in the second shell. In contrast to these three ions, K+ and Cs+ have low charge densities so that they are weakly bonded to their hydration shell. Overall, the structural differences between Ca2+ and Sr2+ are small, but the difference between their coordination numbers relative to their surface areas could potentially be used to separate these ions. Moreover, the different decays of the velocity-autocorrelation functions corresponding to these ions indicates that the difference in mass could be used to separate these cations. In this work, we also propose a new definition of the pairing time that is easy to calculate and of physical significance regardless of the problem at hand. (C) 2014 AIP Publishing LLC.

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}, issn = {0021-9606}, doi = {10.1063/1.4896380}, author = {Hartkamp, Remco and Benoit A. Coasne} }