The energy range of the RIXS spectra shown by Ekholm et al. can be modeled by inclusion of 2 core electrons and 36 valence electrons in i.e. 19 (1+18) doubly filled orbitals and 13 unoccupied orbitals, when using a localized F1s core-level. Hence, the large numbers of configuration state functions and valenceexcited states makes it very demanding to perform more accurate Complete Active Space Self Consistent Field (CASSCF)/Complete Active Space Perturbation Theory (CASPT2)/N-Electron Valence Perturbation Theory (NEVPT2) calculations with an (38e,32o) active space. This is perhaps a good candidate to be studied using Density Matrix Renormalization Group (DMRG)-CASSCF/NEVPT2 but solving for a large number of states is a challenge and it was not attempted.