Electronic Structure of the Oxygen Overlayer on Al(100)

We present detailed electronic structure, total- and orbital-density-of-states information for an ordered overlayer of oxygen on Al(100). Our calculations show that $\mathrm{O}\mathrm{}\left(2p\right)\mathrm{}$ levels are split upon chemisorption. We attribute the oxygen-related structure reported in photoemission experiments to $\mathrm{O}\left(2\mathrm{}{p}_{\sigma }\right)$ levels broadened by band-structure and crystalfield effects. The $\mathrm{O}\left(2\mathrm{}{p}_z\right)$ levels are predicted to disperse significantly due to hybridization with the substrate and may be observable in angularly resolved photoemission experiments.