Neese and co-workers 106 have shown that reasonable agreement with experimental L-and M-edge XANES of bulk transition metal oxides and sulfides can be obtained using small cluster models, e.g., with only six Ti atoms for TiO 2 or even one Fe atom for FeS 2 (s). To investigate convergence using the new CAM-B3LYP/CIS method, we examined TiO 2 clusters of varying size, up to 10 TiO 2 formula units. Oxygen K-edge spectra are shown in Fig. and consists of two near-edge peaks representing excitations into Ti(3d) t 2g and e g MOs. These peaks are well separated in the TiO 2 monomer but quickly converge as additional formula units are added but the relative intensities of these two features are reversed in larger clusters Fig. : Oxygen K-edge spectra for (TiO2)10, computed using CAM-B3LYP/CIS with different basis sets. All spectra were computed using 1000 transition energies broadened using a Gaussian width of 0.3 eV.