State of the Surface of Polycrystalline Silver after Exposure to Activated Oxygen

Resumo

The physical and chemical properties of materials are greatly influenced by the state of their surface layers. In turn, the characteristics of the surface depend, for example, on the processes of absorption from a gas medium. In this study, by in situ measurements, the surface layers of polycrystalline silver exposed to external activated oxygen from different sources are investigated. For sources of activated oxygen, water vapor at a temperature of 1073 K and an ion source that makes it possible to obtain an oxygen ion beam with the energy 100–300 eV (5 μA/cm²) are used. It is established that, after treatment, the composition of AgO and Ag₂O in the surface layers of silver includes, apart from atomic oxygen, molecular oxygen and silver in the zero-valence state. From estimates of the ratio between the intensities of spectroscopy peaks related to silver and oxygen components, it can be concluded that there exist associative forms of oxygen in the surface layers of silver. An increase in Ag 3d_5/2–Ag 3d_3/2 spin–orbit splitting is detected, which suggests that there are oxidized silver nanoparticles on the surface.