Previous experimental XAS on the Al L2,3-edge propose that the location of the CBM is governed by the charge transfer from Al to O atoms, specifically between the O 2p states at the VBM and Al 3s states at the CBM. The eDOS shown in Fig. confirms these experimental assignments of the orbital character and is consistent across each of the 45 configurations in the a-Al2O3 model. Further, as Fig. indicates, these localized states at the CBM, which appear as the pre-edge in the XAS, arise from both Al(IV) and Al(V) coordination geometries. The pre-edge feature in both coordination geometries is present at 1562 eV, making it impossible to distinguish the individual contribution from either of the two geometries experimentally. The ability to deconvolute the spectral features arising form either Al(IV) or Al(V) contributions is therefore a unique feature of calculating the XAS from first principles. While such deconvolution is routinely applied in crystalline systems , this result demonstrates the capability of performing a similar analysis using a joint NMR and XAS analysis on an amorphous material, and determining the orbital character of these states using first principles calculations of the eDOS. 6 Computed electronic density of states for amorphous alumina. Total electronic density of states separated by atom and orbital contribution shows that a-Al2O3 is a wide bandgap insulator, with a PBE calculated gap of 2.6 eV. States at the top of the valence band, near the fermi level are primarily O p states, with states in the conduction band minimum being primarily Al s (detail shown inset top right). The dashed grey line is the sum of these states, and the total density of states was broadened using a Gaussian broadening scheme of width 0.1 eV, as implemented in OptaDOS . The Fermi level is set to 0 eV for all configurations. Two localized states at 3.2 and 4.2 eV above the Fermi level have Al s character and mixed Al s,p character, respectively.