High-pressure optical studies on sulfur to 121 GPa: Optical evidence for metallization.

The pressure dependence of the optical absorption edge to 78 GPa and the reflectivity to 121 GPa were measured in sulfur from 0.5 to 3.5 eV in a diamond anvil cell. Our optical results show no evidence of metallic behavior below 95 GPa. A discontinuous change in absorption was observed at 23 GPa. The absorption edge is about 1 eV at 50 GPa, the pressure at which poor metallic like behavior of sulfur was suggested earlier based on the measurement of the temperature dependence of the electrical resistance