Abstract
The dynamic structure factor of glycerol and LiCl:6O glasses, measured by inelastic x-ray scattering, shows modes dispersing linearly with momentum in the 2-8 region. This finding demonstrates that acousticlike propagating modes can exist in glasses up to wavelengths comparable to interparticle separations. It also shows that the boson peak, a feature systematically observed in the same energy region spanned by these excitations, must have a contribution from this propagating collective dynamics, and not only from possible localized modes.
- Received 19 December 1995
DOI:https://doi.org/10.1103/PhysRevLett.76.3356
©1996 American Physical Society