XAS spectra of mechanically milled TiO2

We report the structural phase transformation of a rutile-type TiO2 during mechanical milling measured by x-ray absorption spectroscopy. The pre-edge peaks near the Ti K edge consists of four components caused by the transitions to the ligand-field-split 3d orbitals hybridized with 4p states and the 4p-4s hybridized level. One of the 3d-4p transitions grows remarkably with increasing the milling time, while the others remain unchanged during the milling. We discuss the features from the structural point of view.