Self-consistent electronic band-structure determination of the chemisorption bond length of oxygen on Al(111)

The electronic structure of a five-layer Al(111) film with an adsorbed oxygen overlayer on each side is calculated by the self-consistent linearized augmented plane wave (LAPW) method with $d_z$, the interplanar distance between the oxygen and Al surface plane set equal to 1.33 Å in accordance with the value given by low-energy electron diffraction measurements. Comparison of the results (work function, position, and dispersion of the O $2p$ bands) with our earlier self-consistent LAPW results obtained with $d_z=0.70\mathrm{}$ Å [the extended x-ray absorption fine-structure (EXAFS) value] and with experiment shows that a definite choice can be made of the correct geometry for the chemisorption phase. We find better agreement when the EXAFS value of $d_z$ is used and conclude that the length of the chemisorption bond distance, O—Al, on Al(111) is 1.79 Å as given by the EXAFS experiment.