关键词: 氧化铁, 纳米相材料, X射线近边吸收谱

α-Fe~2O~3 nanoparticles were chosen to study nanostructured materials by using X-ray absorption near edge structure (XANES) technique. It shows that oxygen K-edgy XANES spectra of all α- Fe~2O~3 nanoparticles of different sizes (3 nm, 10 nm and 55 nm) are different from that of commercial α-Fe~2O~3 coarse particles. the key feature with α-Fe~2O~3 nanoparticles is the occurrence of a new absorption peak labeled B in this paper. It reveals that peak B is attributed to the new states formed by the 2p states of grain boundary oxygen hybridized with iron 4s and 4p states. Further studies suggest that hybridization of oxygen 2p states with 3d metal states, mainly e~g orbital, increases as α-Fe~2O~3 nanoparticles decrease in their size, resulting in a bigger distortion of oxygen octahedrally local symmetry around the iron. Finally, we obtained both oxygen K-edge XANES spectra by making α-Fe~2O~3 nanoparticles (3 nm) directly for the experiment and making the same size nanoparticles after grinding. It proves that there is a special coordination force existing in nanostructured α-Fe~2O~3.

Key words: IRON OXIDE, NANOPHASE MATERIALS