XFH TP-DFT: An alternative description of the potential of the lowest core-excited state was obtained with the XFH TP-DFT protocol in the CP2K program suite . Calculations of SF 6 was performed in a cubic cell with side 20 Å and a Poisson solver for isolated systems using a 600 Ry kinetic energy cut-off for the plane wave part of the description of the electron density in the Gaussian augmented plane wave (GAPW) method. These were all-electron calculations employing the B3LYP functional and def2-TZVP basis sets . Broken symmetry was used to facilitate the description of a ground state with unrestricted wave function in the dissociation limit. Subsequent to the SCF of the ground state wave function, all seven 1s orbitals were involved in the localization to obtain a F1s orbital on the fluorine atom, which was core-excited in the XFH TP-DFT protocol .