Effect of vibrations on the pre-edge features of x-ray absorption spectra

Christian Brouder (1) , Delphine Cabaret (1) , Amélie Juhin (1) , Philippe Sainctavit (1)

1 IMPMC - Institut de minéralogie et de physique des milieux condensés

The influence of atomic vibrations on x-ray absorption near edge structure (XANES) is calculated by assuming that vibrational energies are small with respect to the instrumental resolution. The resulting expression shows that, at the K-edge, vibrations enable electric dipole transitions to 3s and 3d final states. The theory is applied to the K-edge of Al in Al2O3 corundum and of Ti in TiO2 rutile and compared with experiment. At the Al K-edge, sizeable transitions towards 3s final states are obtained, leading to a clear improvement of the agreement with experimental spectra. At the Ti K-edge, electric dipole transitions towards 3d final states explain the temperature dependence of the pre-edge features.

Mots clés: x-ray absorption spectra; thermal vibrations

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Christian Brouder, Delphine Cabaret, Amélie Juhin, Philippe Sainctavit. Effect of vibrations on the pre-edge features of x-ray absorption spectra. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 81 (11), pp.115125. ⟨10.1103/PhysRevB.81.115125⟩. ⟨hal-00438559⟩