A Raman spectroscopic study of shocked single crystalline quartz

We have carried out a Raman Spectroscopic study of single crystalline quartz samples shocked to peak pressures up to 31.4GPa. Samples shocked to above 22 GPa show shifts in peak positions consistent with the quartz being under tensile stress, and new broad bands associated with the formation of high density SiO₂ glass appear in the spectra. These changes are accompanied by an increase in the lattice parameters of the quartz. Formation of the diaplectic glass could be due to a metastable melting event, or spinodal lattice collapse on attainment of a mechanical stability limit of crystalline quartz, as suggested by previous studies of pressure-induced amorphization in static pressurization experiments on SiO₂ and GeO₂ polymorphs.