XPS and XAS study of oxygen coadsorbed with a dispersed phase of K on graphite

• Published in: Surface science 2001-08, Vol.488 (1), p.1-6
• Main Authors: Puglia, C., Bennich, P., Hasselström, J., Brühwiler, P.A., Nilsson, A., Li, Z.Y., Rudolf, P., Mårtensson, N.
• Format: Article
• Language: English
• Subjects: Adsorbed layers and thin films; Alkali metals; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electron and ion emission by liquids and solids; impact phenomena; Exact sciences and technology; Graphite; Oxygen; Photoemission and photoelectron spectra; Physics; Solid-fluid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); X-ray absorption spectroscopy; X-ray photoelectron spectroscopy
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(01)01143-8

The adsorption of O 2 onto a dispersed (low coverage) phase of K on graphite has been characterized by X-ray photoemission and X-ray absorption spectroscopy. We identify two oxygen adsorption phases before physisorbed oxygen appears. The first species dominates at low O 2 exposures whereas the second one, which is probably due to oxygen adsorbed in a superoxo-like configuration (O − δ 2, δ⩽1), is dominant at higher oxygen coverage. As a function of increasing oxygen dose, we confirm that the charge, initially donated by the potassium adlayer to the graphite, is gradually withdrawn from the substrate.