Pressure-induced solidifications of liquid sulfur below and above λ-transition*

Two kinds of glassy sulfurs are synthesized by the rapid compression method from liquid sulfur at temperatures below and above the lambda-transition point. The glassy sulfur has different colors and transparencies, depending on temperature, which may inherit some structural information from the l-transition. Raman spectrum studies of these samples show that a large fraction of polymeric chains exist in the glassy sulfur, even in the one solidified from T < T-lambda. We find that a higher compression rate instead of a higher temperature of the parent liquid captures more polymeric chains. Pressure-induced glassy sulfur presents high thermal stability compared with temperature quenched glassy sulfur and could transform into liquid sulfur directly without crystallization through an abnormal exothermic melting course. High energy x-ray diffraction is utilized to study the local order of the pressure-induced glassy sulfur.