X-Ray Diffraction Study on Structural Change in Liquid Selenium under High Pressure

Abstract

X-ray diffraction experiments on liquid selenium have been performed near the melting temperatures in a pressure range from 2.6 to 4.9 GPa. At atmospheric pressure, liquid Se consists of long-chain molecules. The structure factor at 2.6 GPa was similar to that at ambient pressure. Above 3.5 GPa, however, the shape of the structure factor started to change. The ratio of the height of the first peak to that of the second peak increased with increasing pressure. The change of the structure of liquid Se is discussed in connection with a proposed semiconductor-metal transition in liquid Se under high pressure.