Surface Oxidation of Supported, Size-Selected Silver Clusters
| Autor: | Ueli Heiz, Philipp Heister, Aras Kartouzian, Tobias Lünskens, Constantin A. Walenta |
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| Rok vydání: | 2017 |
| Předmět: |
Chemistry
Analytical chemistry chemistry.chemical_element Resonance Nanochemistry Partial pressure 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Oxygen 01 natural sciences Biochemistry 0104 chemical sciences Cluster (physics) Surface second harmonic generation General Materials Science Surface plasmon resonance Spectroscopy 0210 nano-technology |
| Zdroj: | Journal of Cluster Science. 28:2401-2408 |
| ISSN: | 1572-8862 1040-7278 |
| DOI: | 10.1007/s10876-017-1213-1 |
| Popis: | We use surface second harmonic generation spectroscopy (s-SHG) to study the oxidation of supported, size-selected silver clusters under ultra-high vacuum conditions. The oxidation reaction of small silver clusters between $$\hbox {Ag}_{9}$$ and $$\hbox {Ag}_{55}$$ is monitored by means of their localized surface plasmon resonance. We observe a rapid decline of the SH-intensity, as soon as cluster samples are exposed to an oxygen partial pressure of $$5 \times 10^{-6}$$ mbar, which is attributed to the formation of silver–oxygen-bonds. The evolution of the SH-intensity under exposure to oxygen shows a double-exponential character for all investigated cluster sizes. Since the oxidation of single crystalline silver surfaces follow single-exponential Langmuir-kinetics, the two independent pathways of SH-intensity loss are attributed to a surface- and an interface-oxidation of supported clusters, respectiveley. For small cluster sizes, a complete loss of the SH intensity is obtained, which suggests the complete oxidation of the clusters. For larger clusters a plasmonic resonance is still observed after oxidation, indicating a residual free-electron density. |
| Databáze: | OpenAIRE |
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