Small angle X-ray scattering measurements for supercritical fluid metals such as selenium and mercury have been carried out using synchrotron radiation at SPring-8 to study density fluctuations near the liquid-vapor critical points. The absolute value of the scattering intensity was estimated from measurements on compressed He gas, a method developed using the in-house X-ray source at Hiroshima University. The observed scattering intensity of fluid selenium increases when one approaches the isochore of the critical density with decreasing pressure. The correlation length of the density fluctuations and the long wave length limit of the structure factor, S(0), are deduced to be 16.5 Å and 31 at 1680 °C and 459 bar using the Ornstein-Zernike formula. Based on these data, the density fluctuations in fluid selenium are discussed.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry