A density functional theory study of ordered oxygen overlayers on Ir(100)

Using density-functional theory (DFT) calculations, we study the adsorption of oxygen on Ir(100) as a function of coverage up to 1.0 monolayer and compare the results with available findings for other systems. The p(1 × 2)-O overlayer is shown to be most favorable on Ir(100), in good agreement with experimental findings. The stability of oxygen overlayers and induced work function changes are analyzed. Coverage-dependent modifications of the surface d-band electronic structures are discussed in detail and we find a near-linear correlation between the surface d-band center and the d-band width for the O/Ir(100). The dependence of the adsorption energy on the d-band center exhibits some exceptions in comparison with that of O/Pt(111)