THE SURFACE ELECTRONIC-STRUCTURE OF OXYGEN ON PT(001)(1X1)

The surface embedded Green function (SEGF) method has been used to perform self-consistent calculations of the surface electronic structure of p(1 x 1) oxygen on Pt(001). The calculated O/Pt(001) work function is increased by 1.19 eV over the 5.92 eV previously obtained for clean Pt(001)(1 x 1). Both are in very good agreement with the experimental values of 1.0-0.1 and 5.9 + 0.1 eV, respectively. Our calculated difference-DOS curve is in good agreement with UPS difference spectra. Calculated surface state/surface resonance bands are compared with those obtained for Pt(001)(1 x 1) and for an isolated oxygen monolayer. Total and difference charge density plots are used to illustrate details of O-Pt bonding. Analysis of the surface charge density shows a reduction of surface stress upon oxygen chemisorption, indicating oxygen stabilization of the (1 x 1) phase.