Shock induced splitting of the triply degenerate Raman line in diamond

Strain-induced symmetry changes in diamond have been observed in shock compression experiments. The experimental method utilizes time-resolved Raman spectroscopy to probe the diamond structure behind the shock front. Peak longitudinal stresses up to 50 GPa were achieved by uniaxial strain loading. Strain applied along the [100] and [110] directions is predicted to partially or completely lift the triple degeneracy of the ambient Raman line. The degenerate Raman line was observed to split in accordance with the predicted behavior. The observed changes, despite the large nonhydrostatic stresses, are reversible.