Coordination octahedron distortion effect on x-ray absorption fine structures of titanium in the rutile titanium dioxide

摘要

We have computed the x-ray absorption spectrum for the Ti K-edge in rutile titanium dioxide (TiO2) in the frame of the multiple scattering approach, varying the atom positions within the coordination sphere. This allowed us to understand the origin of the absorption structure variation. The analysis has been achieved by making distortions of the axial and equatorial Ti-O distances or of the Oeq-qq-Oeq equatorial angle along the c axis. Computations are performed using FEFF (version 6) code for TiO2 with Dirac-Hara and Hedin-Lundqvist exchange potentials. From the results, we can better understand why the amplitude of one or several structures is modified referring to TiO2, when a variation of the local geometry occurs.