Publication
Physical Review Letters
Paper

Crossovers in the density of states of fractal silica aerogels

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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. © 1990 The American Physical Society.

Date

20 Aug 1990

Publication

Physical Review Letters

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