A first principles study on the solvation and structure of SO{sub 4}{sup 2-}(H{sub 2}O){sub n}, n=6-12
- Department of Chemistry, and Centre for Scientific Modeling and Computation, Chinese University of Hong Kong, Shatin, Hong Kong (China)
The structures of hydrated sulfate clusters, SO{sub 4}{sup 2-}(H{sub 2}O){sub n} with n=6-12, are obtained by density functional theory calculations. For SO{sub 4}{sup 2-}(H{sub 2}O){sub 12}, two structures with symmetric distribution of H{sub 2}O molecules around the sulfate group are favored in energy. The structures for the smaller clusters, SO{sub 4}{sup 2-}(H{sub 2}O){sub n} with n=6-11, are obtained by taking away one H{sub 2}O molecule successively from the two symmetric SO{sub 4}{sup 2-}(H{sub 2}O){sub 12} isomers. The hydrogen bonding between the sulfate O atoms and H{sub 2}O molecules are strong. So are the hydrogen bonds among H{sub 2}O molecules, which are facilitated by the structure of the polyatomic sulfate group. The solvation energy is quite large (often exceeding 15 kcal/mol). The patterns for structural and energy changes as the cluster size increases are very different from the well studied hydrated halide ions, although the competition between solute-solvent and solvent-solvent interactions is again an important factor. Ab initio molecular dynamics simulations also show 'crowding' effects in the first solvation of SO{sub 4}{sup 2-}(H{sub 2}O){sub 12} at raised temperature.
- OSTI ID:
- 20658022
- Journal Information:
- Journal of Chemical Physics, Vol. 121, Issue 17; Other Information: DOI: 10.1063/1.1802011; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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