Abstract
The far-infrared absorption for two types of silica glasses (containing and of OH) has been quantitatively investigated in the region at room temperature. An absorption coefficient α(ν) increased with increasing OH content and a broad peak on a plot of vs ν, corresponding to a “boson peak” shifted from 41 to The OH-related absorption increase Δα(ν), showed a monotonic increase with frequency ν in contrast to that previously published. The rate of the absorption increase Δα(ν)/α(ν) showed a rapid decrease with frequency obeying a power-law between and whereas it decreased very slowly below It is suggested on the basis of a noncontinuous network model for the glass that OH ions are not uniformly distributed in silica glass. The light-vibration coupling coefficient determined experimentally is briefly discussed by some models proposed before.
- Received 5 September 1997
DOI:https://doi.org/10.1103/PhysRevB.57.4995
©1998 American Physical Society