In the present study, firstly we simulate the nonresonant F1s XE spectrum as well as RIXS, using the ground state optimized static geometry, at different excitation energies of the fluorine K-edge XA spectrum. These XA, XE, and RIXS spectra are denoted static spectrum simulations. We model the polarization dependent RIXS spectra, with horizontal and vertical polarization of the incident radiation, and find that indeed the localized core-hole picture gives a more accurate reproduction of the experimental RIXS spectra, than when using the delocalized canonical orbitals, due to a breakdown of the parity selection rule. This is indicative of a strong role of vibronic coupling, ultra-fast dissociation and core-hole localization in the F1s RIXS process. In addition, we also computed the electron-hole coupling, and we found negligible couplings for the t 1u and t 2g resonances, as suggested in Ekholm et al. , in contrast to the a 1g resonance.