EXAFS STUDIES ON LIQUID SE-TE MIXTURES

EXAFS measurements of liquid (1-) SeTe mixtures have been carried out both on Se and Te K-edges. From a curve fit analysis, the bond length in 1-Se is estimated to be 2.34A, which is shorter than that in crystalline Se. For 1-Te no single-shell model is good enough to fit the observed EXAFS spectrum. The result with two-shell fit is encouraging and indicate that the neighboring atoms are located at the distances of 2.83A and 3.03A. In the liquid mixtures the atomic arrangement of Se and Te around each central atom is resolved utilizing large difference in the wave-vector dependence of backward scattering amplitude from Te and Se. The temperature variation of the mean square displacement of the SeTe bond is found to be much larger than that of the SeSe one. © 1990.