BOSE PEAK IN THE RAMAN-SPECTRA OF DENSIFIED SIO2 AND GEO2 GLASS UNDERHIGH-PRESSURE

Densified vitreous SiO2 and GeO2 recovered from various high pressures were measured by ambient-pressure Raman scattering. The phonon energi es start to shift at the same pressures as the increase of coordinatio n numbers of Si and Ge at high pressures. The correlation length is es timated from the energy of the Bose peak, which is characteristic of d isordered structure. The shortening of the correlation length in densi fied glass is in accordance with the mixed coordinations.