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-resolv ed Raman spectroscopy to probe the diamond structure behind the shock front. Peak longitudinal stresses 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 th e ambient Raman line. The degenerate Raman line was observed to split in accordance with the predicted behavior. The observed changes, despi te the large nonhydrostatic stresses, are reversible.