The calculated crystal structures of Yb 2 O 3 were almost the same as the previous results with similar calculation conditions . In the core-hole calculations, conventional 1 × 1 × 1, conventional 4×4×4, and 4×4×4 cells were adopted for the cubic, monoclinic, and hexagonal phases, respectively. A Γ-centered 3 × 3 × 3 k-point grid was used for BZ sampling.