| Abstract
| - The structures of Fe2O3 nanoparticles with different sizes were investigated using Fe K-edge X-ray absorptionnear-edge structure (XANES) and the FEFF calculations, as well as surface modification with enediol ligands.The studies not only revealed the existence of under-coordinated Fe sites in the nanoparticles but also confirmedthat these under-coordinated sites were located on the surface. Upon binding of enediol ligands, surface siteswere restructured to octahedral sites. In particular, the nature of the surface defects and their correlation withthe unique properties of the nanoparticles were discussed. Model calculations were conducted for FemOn (m≥ 1, n ≥ 4) clusters of various sizes centered at Fe sites with octahedral (Oh), distorted octahedral (C3v) andtetrahedral (Td) coordination geometry using FEFF8.10 programs. The main features of the calculated spectraagree with the experimental results and were correlated to the density of states, the Fe coordination geometry,and the long-range order of the lattice.
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