However, using TD-DFT the valence excited state energies are reproduced more accurately, we shift the simulated RIXS spectra to match the experimentally obtained elastic line, for individual resonances. The six F1s core orbitals forms Symmetry Adapted Linear Combination of a 1g , t 1u and e g symmetry, see FIG. Ekholm et al. report on the presence of core-hole localization effects and the violation of the parity selection rule in the RIXS spectra which was concluded from the observation of peaks associated electronically dipole forbidden transitions resulting from breaking of the global inversion symmetry. The total RIXS at the |F1s -1 6a 1 1g resonance computed with localized (yellow spectrum) and delocalized core-holes (blue spectrum). Clearly the number of peaks appearing with localized core-hole is larger than when using delocalized core-holes, which preserves selection rules, due to breakdown of symmetry selection rules.