We have also computed S/N atoms as metric that can be compared across cluster sizes and we find that this metric is more similar for all three clusters, ranging from 2.6-7.5 kcal/mol. Consistent with experiment, the MP2-optimized structures afford a localized hole (Fig. ) and a single elongated Al-O bond length (Table ). Starting from these MP2-optimized structure for each cluster, we next performed geometry optimizations at various DFT levels of theory to investigate structural distortion and (de)localization of the hole. As indictors of distortion, Al-O bond lengths around the defect center are listed in Table for several different functionals and their DC-DFT analogues. Spin densities (ρ α -ρ β ) for the a Spin delocalization moves the defect towards the surface oxygen atoms (see Fig. ). Al(OSiH 3 ) 4 cluster are shown in Fig. and for the other clusters in Figs. and.