Raman Studies of Sulfur Crystal (α-S₈) at High Pressures and Low Temperatures

We have studied the temperature and pressure dependence of the vibrational energy levels of orthorhombic sulfur. Spectroscopic measurements were performed using standard Raman equipment; high pressure experiments made use of a diamond anvil cell (DAC). In general all external modes are sensitive to temperature variation in the range 50−300 K; internal modes exhibit a different behavior. It was found that mode energies were more influenced by pressure (0−5 GPa) than by temperature (12−300 K). In addition it was found that the intensities of prominent features of the Raman spectrum were pressure dependent.