The adsorption energies of simple atomic adsorbates are coverage dependent. We use density-functional theory to show that the coverage dependence is due to an adsorbate-induced modification of the surface $d$-band structure. We developed a simple model for predicting the $d$-band widths of clean and adsorbate-covered metallic surfaces using a tight-binding formalism. The new model can be used in conjunction with the $d$-band adsorption model to estimate adsorption energies as a function of coverage.

• Received 9 June 2010

DOI:https://doi.org/10.1103/PhysRevB.82.045414