XAFS MEASUREMENTS ON MOLTEN SILVER-HALIDES

X-ray absorption fine structure (XAFS) measurements on molten silver halides and Ag(Br1-xIx) near their melting temperatures have been carried out around the Ag K absorption edge for the first time to obtain information on the partial structures. Clear oscillations are observed in the XAFS spectra far molten AgCl and AgI, while the amplitude of the XAFS oscillations for molten AgBr is considerably reduced. This reduction suggests large fluctuations in the Ag-Br interionic distance. The result of a curve fit analysis for molten AgI shows that about two I ions are coordinated at 2.73 Angstrom around a central Ag ion. This result may indicate that about half of the Ag and I ions contribute to the formation of tetrahedrally coordinated clusters.