Speaker
Thomas Rossi
(EPFL)
Description
The origin of the four pre-edge peaks (1s-3d) in the Ti K-edge XAS spectrum of anatase TiO$_2$ is still actively debated. By combining X-ray Absorption Linear Dichroism with ab-initio finite difference method calculations, we provide an unambiguous assignment of these peaks. These forbidden transitions arise from a strong mixing of the 3d orbitals with 4p$_z$ and 4p$_{x,y}$ orbitals, with an angular momentum dependent chemical shift because of different Ti-O bond distances along $x,y$ and $z$. Interestingly, the above edge region also exhibits a strong linear dichroism related to a significant p-orbital contribution in the multiple scattering region.
Authors
Thomas Rossi
(EPFL)
Prof.
Majed Chergui
(EPFL-SB-ISIC-LSU)
Co-authors
Dr
Daniele Pergolesi
(Thin Films and Interfaces Group)
Prof.
Thomas Lippert
(Thin Films and Interfaces Group)
Dr
Marteen Nachtegaal
(In Situ X-ray Spectroscopy Group)
Dr
Daniel Grolimund
(microXAS Beamline Project)
