A density functional theory study of ordered oxygen overlayers on Ir(100) S.H. Ma, Z.Y. Jiao, X.Z. Zhang, Z.X. Yang and X.Q. Dai Eur. Phys. J. B, 85 6 (2012) 216 Published online: 25 June 2012 DOI: 10.1140/epjb/e2012-20980-x