Structural, dynamical, and transport properties of the hydrated halides: How do At- bulk properties compare with those of the other halides, from F- to I-?

Abstract : The properties of halides from the lightest, Fuoride (F-), to the heaviest, astatide (At-), have been studied in water using a polarizable force-field approach based on molecular dynamics (MD) simulations at the 10 ns scale. The selected force-field explicitly treats the cooperativity within the halide-water hydrogen bond networks. The force- eld parameters have been adjusted to ab initio data on anion/water clusters computed at the relativistic Möller-Plesset second-order perturbation theory level of theory. The anion static polarizabilities of the two heaviest halides, I- and At-, were computed in the gas phase using large and diffuse atomic basis sets, and taking into account both electron correlation and spin-orbit coupling within a four-component framework. Our MD simulation results show the solvation properties of I- and At- in aqueous phase to be very close. For instance, their first hydration shells are structured and encompass 9.2 and 9.1 water molecules at about 3.70 ± 0.05 Å, respectively. These values have to be compared to the F-, Cl-, and Br- ones, i.e., 6.3, 8.4, and 9.0 water molecules at 2.74, 3.38, and 3.55 Å, respectively. Moreover our computations predict the solvation free energy of At- in liquid water at ambient conditions to be 68 kcal mol-1, a value also close the I- one, about 70 kcal mol-1. In all, our simulation results for I- are in excellent agreement with the latest neutron- and X-ray diffraction studies. Those for the At- ion are predictive, as no theoretical or experimental data are available to date.
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Article dans une revue
Journal of Chemical Physics, American Institute of Physics, 2016, 144, pp.124513. 〈10.1063/1.4944613〉
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https://hal.archives-ouvertes.fr/hal-01294362
Contributeur : Valérie Vallet <>
Soumis le : mardi 29 mars 2016 - 11:00:54
Dernière modification le : vendredi 27 juillet 2018 - 16:34:02

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Florent Réal, Andre Severo Pereira Gomes, Yansel Omar Guerrero Martínez, Nicolas Galland, Valérie Vallet, et al.. Structural, dynamical, and transport properties of the hydrated halides: How do At- bulk properties compare with those of the other halides, from F- to I-?. Journal of Chemical Physics, American Institute of Physics, 2016, 144, pp.124513. 〈10.1063/1.4944613〉. 〈hal-01294362〉

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