Crossovers in the density of states of fractal silica aerogels
- 20 August 1990
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 65 (8), 1008-1011
- https://doi.org/10.1103/physrevlett.65.1008
Abstract
Combining neutron and Raman spectroscopies, we identify a succession of regimes in the vibrational dynamics of two aerogels of different microstructures. Aside from the phonon-fracton and fracton-particle mode crossovers, we find an additional crossover that suggests two distinct elastic regimes in the fracton range, which we associate with bending and stretching. Greatly different Debye-Waller factors are found in the two regimes, distinguishing them unambiguously in neutron spectra.Keywords
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