Coexistence of OH phases on Ag(110)

• Published in: Surface science 1995-12, Vol.343 (3), p.176-184
• Main Authors: Canepa, M., Cantini, P., Narducci, E., Salvietti, M., Terreni, S., Mattera, L.
• Format: Article
• Language: English
• Subjects: Angle resolved photoemission; Atom-solid scattering and diffraction - elastic; Chemisorption; Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; General and physical chemistry; Impurity and defect levels; energy states of adsorbed species; Oxygen; Physics; Silver; Solid surfaces and solid-solid interfaces; Solid-fluid interfaces; Solid-gas interface; Surface and interface electron states; Surface chemical reaction; Surface physical chemistry; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thermal desorption spectroscopy; Water
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(95)00819-5

The adsorbed OH phase formed following water reaction on a well-ordered O(3 × 1)-Ag(110) phase (oxygen precoverage 0.33) has been studied by a combined analysis of structural properties (by helium diffraction), of electronic states at surface (by angle resolved ultraviolet photoemission spectroscopy) and by thermal desorption mass spectrometry (TDS). TDS findings, together with the band structure of the OH-induced electronic levels, indicate that the OH phase under investigation is formed by two coexistent subphases, δ and γ′, that are characterized by local coverages 0.5 and 1, respectively. The δ state shows a (1 × 2) translational symmetry and it is ordered over the range scale probed by helium diffraction. The state γ′ displays a (1 × 1) ordering only over the length scale probed by ARUPS. A tentative model of the mosaic structure of the phase is presented. γ′ patches undergo a recombination reaction in a very narrow range of temperature close to 250 K. Desorption of the δ state starts at 265 K being completed at 310 K where the original O(3 × 1)-Ag(110) phase is restored.