Connection between Boson peak and elastic properties in silicate glasses.

Institut Laue-Langevin, BP156, 38042 Grenoble, France(Received 10 February 2009; published 13 May 2009)Inelastic neutron, light, and x-ray scattering are used to investigate the vibrational density of states(VDOS) and the elastic properties of a sodium silicate glass as a function of temperature. The elasticmoduli show the frequency and temperature dependence typical of anharmonic effects. The measuredVDOS spectra, up to and including the excess vibrational density at the boson peak, scale with the Debyelevel only if this is calculated from the high-frequency values of the elastic constants. This emphasizesthat conclusions on the relation between VDOS and elastic properties can be drawn only if anharmonicand relaxational effects are properly taken into account.