High frequency acoustic modes in vitreous Beryllium Fluoride probed by inelastic X-ray scattering

Abstract

Inelastic X-ray Scattering measurements of the dynamics structure factor have bene performed on vitreous Beryllium Fluoride ({\it v-}BeF${}_2$) at $T$=297 K in the momentum transfer, $Q$, range $Q$=1.5$÷$10 nm${}^{-1}$. We find evidence of well defined high frequency acoustic modes. The energy position and linewidth of the excitations disperse with $Q$ as $\propto Q$ and $\propto Q^2$, respectively up to about one half of the first maximum of the static structure factor. Their magnitude compare favorably with low-frequency sound velocity and absorption data. The results indicate worth mentioning similarities of the high frequency collective dynamics of different network forming glasses such as {\it v-}B${}_2$O${}_3$ and {\it v-}SiO${}_2$.

17 pages, 5 .ps figs

References in corpus (1)

• Evidence of short time dynamical correlations in simple liquids

Cited by in corpus (6)

• Is the Fragility of a Liquid Embedded in the Properties of its Glass?
• Anharmonic vs. relaxational sound damping in glasses: II. Vitreous silica
• Fragility and compressibility at the glass transition
• Brillouin and Boson peaks in Glasses from vector Euclidean Random Matrix Theory
• A new way to evaluate x-ray Brillouin scattering data
• A continuum model reproducing the multiple frequency crossovers in acoustic attenuation in glasses