RAMAN STUDIES OF SULFUR CRYSTAL (ALPHA-S-8) AT HIGH-PRESSURES AND LOW-TEMPERATURES

We have studied the temperature and pressure dependence of the vibrati onal energy levels of orthorhombic sulfur. Spectroscopic measurements were performed using standard Raman equipment; high pressure experimen ts made use of a diamond anvil cell (DAC). In general all external mod es are sensitive to temperature variation in the range 50-300 K; inter nal modes exhibit a different behavior. It was found that mode energie s were more influenced by pressure (0-5 GPa) than by temperature (12-3 00 K). In addition it was found that the intensities of prominent feat ures of the Raman spectrum were pressure dependent.