Evidence for a crossover in the frequency dependence of the acoustic attenuation in vitreous silica

Phys Rev Lett. 2006 Jul 21;97(3):035501. doi: 10.1103/PhysRevLett.97.035501. Epub 2006 Jul 18.


We report measurements of the sound attenuation coefficient in vitreous silica, for sound waves of wavelength between 50 and 80 nm, performed with the new inelastic UV light scattering technique. These data indicate that in silica glass a crossover between a temperature-dependent (at low frequency) and a temperature-independent (at high frequency) acoustic attenuation mechanism occurs at Q approximately equal to 0.15 nm(-1). The absence of any signature in the static structure factor at this Q value suggests that the observed crossover should be associated with local elastic constant fluctuations.