X-ray diffraction and Raman scattering measurements on silica xerogels
| Autor: | Maurizio Ferrari, Flavio Rossi, Aldo Fontana, Claudio Masciovecchio, Maurizio Montagna, Giancarlo Ruocco, Francesco Sette, Silvia Caponi, A. Mermet |
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| Rok vydání: | 2002 |
| Předmět: |
Range (particle radiation)
Chemistry Small-angle X-ray scattering Scattering Condensed Matter Physics Molecular physics Electronic Optical and Magnetic Materials symbols.namesake Nuclear magnetic resonance X-ray Raman scattering X-ray crystallography Materials Chemistry Ceramics and Composites symbols Density of states Raman spectroscopy Raman scattering |
| Zdroj: | Journal of Non-Crystalline Solids. :135-141 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/s0022-3093(02)01451-5 |
| Popis: | The dynamics and the structure of silica xerogels at different degrees of densification have been studied by small angle X-ray scattering and Raman scattering, with the aim to investigate the effects of the inhomogeneous structure on the excitations that give rise to the excess in the density of states (Boson peak). The results are compared with those of specific heat measurements on the same samples. The present results show that the existence of the pores, whose medium size is in the 30–60 A range, does not appreciably affect the density of states in the Boson peak frequency range. On the contrary, at lower frequencies ( ω −1 ), a strong pore-size dependence is observed in the Raman spectra. |
| Databáze: | OpenAIRE |
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