Figure plots TiO 2 excitation spectra in the range 500-550 eV, computed at the SRC1-r1/def2-TZVPD level. Given the large shifts that are often required to match experiment in TDDFT calculations, it is not obvious which feature in the full TDKS spectrum is the O(1s) → LUMO transition. For example, we have seen above that the SRC1-r1 functional places the oxygen K-edge at around 532 eV, but if this same TiO 2 calculation is performed at the B3LYP/def2-TZVPD level, the O(1s) → LUMO excitation appears at 515 eV and there is a band of transitions between 515-520 eV. There are prominent features in the same energy region in the TDKS spectra shown in Fig. , but dipole filtering reveals that they are not associated with the oxygen K-edge. Instead, the most intense absorption feature in Fig. is associated with excitation from Ti(2p) orbitals. In this example the oxygen K-edge, which (as in previous examples) appears around 532 eV for the SRC1-r1 functional, includes significant contamination from the titanium L-edge. This contamination, involving excitations originating in the Ti(2p) orbitals, is easily filtered away to expose separate oxygen and titanium spectra, either of which is a good match to the corresponding LR-TDDFT/CVS calculation.