Comparison of RIXS simulations (using delocalized and localized core orbitals) at the |F1s -1 6a 1 1g resonance are presented in FIG. in comparison to experiment. For RIXS calculations with delocalized core orbitals, the parity selection rule only allows for decay to the delocalized core orbital 1t 1u from valence occupied orbitals having gerade(g) symmetry. The sharp peak in the |F1s -1 6a 1 1g resonance around 677.8 eV, at which is due to transitions from 5t 1u and 1t 2u orbital, would be absent, see FIG. ) blue spectrum vs orange spectrum. However, this peak is present and also the sharpest peak in the RIXS spectra. The peaks which arise under conservation of parity selection rules among the relevant orbitals in SF 6 is shown in FIG. (a) along with the corresponding static RIXS spectrum in FIG. ) depicted as the blue spectrum. In contrast in the frame of localized core orbitals, the parity selection rule is broken and the simulated RIXS spectrum, as shown by orange spectrum in FIG. , accounts for all the peaks which are experimentally observed. It should be noted that, even for RIXS, the localized and delocalized pictures are equivalent, if one includes all near-degenerate channels and interference between them. However, since vibronic coupling in the intermediate state often quenches electronic interference , the use of a localized picture neglecting electronic interference constitutes a pragmatic approximation which reproduces experimental observables. Based on this we proceeded to compute the RIXS spectra with a localized core-hole neglecting interference between different core-hole sites, which typical arises due to vibronic coupling. We clearly see in FIG. ) that the spectra obtained using localized core-hole clearly shows all possible transitions and all the peaks in the experimental spectra can be accounted for.