Eur. Phys. J. B 83, 437-443 (2011)
https://doi.org/10.1140/epjb/e2011-20404-7

Regular Article

Sulphur overlayers on Ir(100) and its effect on the adsorption of CO: a DFT study

College of Physics and Information Engineering, Henan Normal University, Xinxiang, Henan 453007, P.R. China

^a e-mail: msh8586@163.com

Received: 28 May 2011
Received in final form: 21 July 2011
Published online: 24 October 2011

Abstract

Ordered sulphur overlayers adsorbed on Ir(100) surface are studied with different coverage ranging from 0.11 to 1.0 ML. Calculations indicate that atomic S adsorbs favourably in hollow sites, forming strong covalent bonds with the substrate surface and the adsorption energy is nearly unchanged at lower coverages (θ_S ≤ 0.50 ML). In good agreement with experimental observations, the p(2 × 2)-S and c(2 × 2)-S are predicted to be the most stable overlayers. The obtained surface electronic structure modifications induced by sulphur adsorption are coverage-dependent and the results are in accordance with the rectangular band and the Hammer-Nørskov models. Moreover, the effect of sulphur on the adsorption of CO is discussed in the p(2 × 2)-(S + CO) overlayer on Ir(100).