XAFS MEASUREMENTS AT HIGH-TEMPERATURES AND PRESSURES

The method of XAFS measurements at high temperatures and pressures for supercritical fluids with high critical constants have been developed. An internally heated high-pressure vessel made of super-high-tension steel and a polycrystalline sapphire cell of our own design permit XAFS measurement up to 800 bar. XAFS experiments were carried out at high temperatures up to 1600 °C, and high pressures up to 150 bar. XAFS spectra of liquid Se at 1300°C and 150 bar, and dense Se vapor at 1600°C and 150 bar have been obtained and clear oscillations are observed at these temperatures. © 1995 American Institute of Physics.