Structures of actinide complexes: combining DFT calculations, EXAFS spectroscopy, and thermodynamic speciation


Structures of actinide complexes: combining DFT calculations, EXAFS spectroscopy, and thermodynamic speciation

Tsushima, S.; Hennig, C.; Ikeda, A.; Rossberg, A.; Scheinost, A.

Density functional theory (DFT) calculations in combination with the polarizable continuum model (PCM) are a very useful method for obtaining the structure of actinide complexes in aqueous solution. The accuracy in energy, however, is often not sufficient to find a definite answer on whether ligands are coordinated in monodentate or bidentate fashion [1], pinpointing the limitations of working solely with theoretical calculations. Extended X-ray absorption fine structure (EXAFS) spectroscopy is a powerful experimental method for the determination of structures of aqueous complexes; the limitation is, however, a relatively poor distal resolution and often no information on the spatial orientation, making the resolution of co-existing species difficult. Finally, thermodynamic calculations also do not always provide accurate information.
Therefore, we combined all three methods, DFT, EXAFS, and thermodynamic speciation, to study the speciation and structure of actinide complexes in aqueous solution. We will show examples of uranyl(VI) ligation towards water, carbonate, and sulfate. We will also address the formation of polymeric complexes.

  • Invited lecture (Conferences)
    American Chemical Society 234th National Meeting, Symposium: Computational Actinide and Transactinide Chemistry: Progress and Perspectives, 19.-23.08.2007, Boston, United States

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Publ.-Id: 9899