X-ray absorption spectroscopy of scandium oxide polymorphs.

Area of Science:

• Materials Science
• Solid State Physics
• Computational Chemistry

Background:

• Scandium oxide (Sc₂O₃) is a rare-earth oxide with technological importance.
• Limited supply necessitates a deeper understanding of its various crystalline phases.
• Existing data on Sc₂O₃ polymorphs is incomplete.

Purpose of the Study:

• To investigate the structural and electronic properties of scandium oxide (Sc₂O₃) polymorphs.
• To compare experimental X-ray absorption spectroscopy (XAS) data with theoretical calculations for different Sc₂O₃ phases.
• To elucidate the role of electron-hole correlations in XAS spectra.

Main Methods:

• Experimental X-ray absorption spectroscopy (XAS) at the O K-edge and Sc L_2,3-edge.
• Ab initio computation of six Sc₂O₃ polymorphs, including high-pressure and predicted structures.
• Solution of the Bethe-Salpeter equation (BSE) and independent-particle approximation (IPA) for spectral simulation.

Main Results:

• Good agreement between simulated spectra (BSE) and experimental XAS measurements for cubic and trigonal Sc₂O₃ phases.
• Identified significant similarities between cubic and high-pressure trigonal Sc₂O₃ polymorphs.
• Highlighted the crucial role of electron-hole correlations, especially at the O K-edge, in spectral features.

Conclusions:

• The study provides detailed spectral fingerprints for various Sc₂O₃ polymorphs.
• Findings support in situ characterization of scandium oxide materials.
• The research contributes to informed sustainable management of rare-earth materials.