Vitreous silica distends in helium gas: acoustic versus static compressibilities.
Sound velocities of vitreous silica are measured under He compression in the pressure range of 0-6 GPa by Brillouin light scattering. It is found that the well-known anomalous maximum in the pressure dependence of the compressibility is suppressed by He incorporation into the silica network. This shows that the elastic anomaly relates to the collapse of the largest interstitial voids in the structure. The huge difference between the static and the acoustic compressibilities indicates that the amount of incorporated helium still increases at 6 GPa.
Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095 Montpellier, France.
Coralie
C
Weigel
Alain
A
Polian
Mathieu
M
Kint
Benoit
B
Rufflé
Marie
M
Foret
René
R
Vacher