ESR study of fullerene black
| Autor: | S.D. Kushch, Alexander V. Kulikov, P. V. Fursikov, V. R. Bogatyrenko |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
inorganic chemicals
Fullerene Solid-state physics Annealing (metallurgy) Chemistry Radical Conjugated system Photochemistry Atomic and Molecular Physics and Optics Catalysis law.invention Condensed Matter::Materials Science law Molecule Condensed Matter::Strongly Correlated Electrons skin and connective tissue diseases Electron paramagnetic resonance |
| Zdroj: | Applied Magnetic Resonance. 22:539-550 |
| ISSN: | 1613-7507 0937-9347 |
| DOI: | 10.1007/bf03166131 |
| Popis: | Fullerene black before and after annealing at 850°C has been studied by electron spin resonance (ESR). For initial fullerene black, the ESR line exhibits wide wings and its shape is caused by magnetic dipole-dipole interactions between radicals localized randomly on the carbon surface. Dioxygen decreases reversibly the amplitude of the ESR line without changes in its shape, width (0.19 mT) andg-factor (2.0022). This is explained by the assumption that dioxygen molecules adsorbed on the surface broaden strongly ESR lines only of neighboring radicals. For annealed fullerene black, the ESR line is Lorentzian, dioxygen reversibly broadens the line, and theg-factor decreases with the broadening of the line by dioxygen. This is explained by radical-radical and radical-dioxygen spin exchange interactions via conjugated bonds formed in the course of annealing. Flattening of curved carbon surfaces after annealing explains in a uniform way changes in parameters of ESR lines and in reactivity and catalytic activity of fullerene black. |
| Databáze: | OpenAIRE |
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