Revisit of XPS Studies of Supersonic O-2 Molecular Adsorption on Cu(111): Copper Oxides

We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk Cu2O(111) surface and "8" and "29" oxide structures on Cu(111) prepared using a 0.5 eV O-2 supersonic molecular beam. We propose a new structural model for the "8" oxide structure and also confirm the previously proposed model for the "29" oxide structure on Cu(111), based on the O 1s XPS spectra. The detection angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the (root 3 x root 3)R30 degrees Cu2O(111). We also report electronic excitations that O 1s electrons suffer.