Interpretation of the Co K-edge EXAFS in LaCoO3 using molecular dynamics simulations

Temperature dependent (180–400 K) Co K-edge EXAFS spectra from perovskite-type rhombohedral (R3¯c) LaCoO3 have been successfully interpreted using a combination of classical NVT molecular dynamics (MD) and ab initio multiple-scattering (MS) theory. The method allowed us to account entirely for thermal disorder and to interpret reliably the contribution from the coordination shells beyond the first one into the total EXAFS spectrum taking into account many-body effects. The best agreement between experimental and configuration-averaged EXAFS spectra was obtained for pure ionic La3+ and partially ionic Co1.35+ and O1.45− charges indicating the mixed ionic-covalent character of the Co―O bonds.