Emission energy and (energy loss) at O h geometry (eV) in the SI. When dynamical effects of the F 5 S-F bond dissociation are included, i.e. the vibrational profile of the dissociative |F1s -1 6a 1 1g state is included in the absorption spectra, we clearly see that the DFT-ROCIS and TD-DFT core-excited PES fail to produce the experimental broadness of the XA spectrum. This could be due to two reasons, i.e. (i) In the one dimensional cuts in the PES for DFT-ROCIS and TD-DFT, the curves are too shallow and (ii) the absence of other nuclear degrees of freedom. As discussed earlier in Methods II section, the model essentially constitutes of the only SF 5 -F bond dissociation and other angular distortion modes are neglected. The steepness of the core excited states can also be strongly affected by the neglect of these other degrees of freedom, which would result in underestimation of the broadening of the XA spectrum. The methods which we employ here like TD-DFT and DFT-ROCIS lack proper accounting of the the core-hole relaxation effects, which in turn could change the intermediate state PES.