DENSITY OF LIQUID TELLURIUM UNDER PRESSURE

A new method for density measurements by means of X-ray absorption und er high pressure and high temperature using a multi-anvil apparatus, c ombined with a synchrotron radiation source, was developed. To overcom e the effect of the variation of the sample thickness under pressure, a sapphire ball was put in the sample capsule to calibrate the thickne ss, and the intensity of the transmitted X-ray beam was measured as a function of sample position. Densities of crystalline and liquid tellu rium were measured up to 4 GPa and up to 770 degrees C, Discontinuous changes of density at the Te(I)-Te(II) transition and at melting were clearly observed. The compressibility of liquid Te under pressure was obtained. The existence of the recently proposed liquid-liquid phase t ransition under high pressure is discussed.