Coverage-dependent adsorption and desorption of oxygen on Pd(100)
| Autor: | Otto Berg, Angela den Dunnen, Ludo B. F. Juurlink, Sandra Wiegman, Leon Jacobse |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Chemistry
Thermal desorption spectroscopy Nucleation Analytical chemistry General Physics and Astronomy chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Oxygen Dissociation (chemistry) 0104 chemical sciences Overlayer Adsorption Desorption Physics::Atomic and Molecular Clusters Physics::Chemical Physics Physical and Theoretical Chemistry 0210 nano-technology Molecular beam |
| Zdroj: | JOURNAL OF CHEMICAL PHYSICS, 144(24), 244706 JOURNAL OF CHEMICAL PHYSICS |
| Popis: | We have studied the adsorption and desorption of O2 on Pd(100) by supersonic molecular beam techniques and thermal desorption spectroscopy. Adsorption measurements on the bare surface confirm that O2 initially dissociates for all kinetic energies between 56 and 380 meV and surface temperatures between 100 and 600 K via a direct mechanism. At and below 150 K, continued adsorption leads to a combined O/O2 overlayer. Dissociation of molecularly bound O2 during a subsequent temperature ramp leads to unexpected high atomic oxygen coverages, which are also obtained at high incident energy and high surface temperature. At intermediate temperatures and energies, these high final coverages are not obtained. Our results show that kinetic energy of the gas phase reactant and reaction energy dissipated during O2 dissociation on the cold surface both enable activated nucleation of high-coverage surface structures. We suggest that excitation of local substrate phonons may play a crucial role in oxygen dissociation at any coverage. |
| Databáze: | OpenAIRE |
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