d-Orbital Occupancy Systematics of 4d/5d Row Transition Metal Oxides by X-Ray Absorption Near Edge Spectra (XANES)

XANES L₂ and L₃ edge X-Ray Absorption Near Edge Spectra (XANES) for 4d and 5d row transition metals (TM) oxides are assumed to be directly reflecting unoccupied d-orbitals influenced by the local symmetry of the metal ion¹. XANES L₂ and L₃ edge data analysis through non-linear curve fitting allows for a unique, efficient look at the structural eccentricities of transition metal oxides. In this way it is possible to determine the oxidation state of a material as well as its site symmetry. We have used non-linear least-squares fitting across the near-edge region of the various 4d row and 5d row TM oxides in order to investigate the systematics of the d-orbital occupancy and the XANES white line features for t_2g and e_g symmetry orbitals. The statistics have already shown promising trends to be expected in 4d and 5d row level transition metal oxides. The systematics obtained by these results provide crucial information for the synthesis of the new materials with specific electronic structures and crystal symmetries.
¹ Megan E. Fieser et al., Chem. Sci., 2017, 8, 6076–6091