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Author Réal, Florent ♦ Severo Pereira Gomes, André ♦ Guerrero Martínez, Yansel Omar ♦ Vallet, Valérie ♦ Ayed, Tahra ♦ Galland, Nicolas ♦ Masella, Michel
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ELECTRON CORRELATION ♦ EXPERIMENTAL DATA ♦ FREE ENERGY ♦ HALIDES ♦ HYDRATION ♦ L-S COUPLING ♦ MOLECULAR DYNAMICS METHOD ♦ PERTURBATION THEORY ♦ SIMULATION ♦ X-RAY DIFFRACTION
Abstract The properties of halides from the lightest, fluoride (F{sup −}), to the heaviest, astatide (At{sup −}), 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-field 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{sup −} and At{sup −}, 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{sup −} and At{sup −} 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{sup −}, Cl{sup −}, and Br{sup −} 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{sup −} in liquid water at ambient conditions to be 68 kcal mol{sup −1}, a value also close the I{sup −} one, about 70 kcal mol{sup −1}. In all, our simulation results for I{sup −} are in excellent agreement with the latest neutron- and X-ray diffraction studies. Those for the At{sup −} ion are predictive, as no theoretical or experimental data are available to date.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-03-28
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 144
Issue Number 12


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