Local hydrated structure of an Fe2+/Fe3+ aqueous solution: an investigation using a combination of molecular dynamics and X-ray absorption fine structure methods
- Received Date: 2012-04-27
- Accepted Date: 2012-08-14
- Available Online: 2013-03-05
Abstract: The hydrated shell of both Fe2+ and Fe3+ aqueous solutions are investigated by using the molecular dynamics (MD) and X-ray absorption structure (XAS) methods. The MD simulations show that the first hydrated shells of both Fe2+ and Fe3+ are characterized by a regular octahedron with an Fe-O distance of 2.08Å for Fe2+ and 1.96Å for Fe3+, and rule out the occurrence of a Jahn-Teller distortion in the hydrated shell of an Fe2+ aqueous solution. The corresponding X-ray absorption near edge fine structure (XANES) calculation successfully reproduces all features in the XANES spectra in Fe2+ and Fe3+ aqueous solution. A feature that is located at energy 1 eV higher than the white line (WL) in an Fe3+ aqueous solution may be assigned to the contribution of the charge transfer.