DAFS STUDY OF INTERMEDIATE-RANGE ORDER IN [[upsilon]]-GeO₂ and [[upsilon]]-GeSe₂. D.L. Price, M-L Saboungi, Argonne National Laboratory, Argonne, Illinois 60439, P. Armand, University of Montpellier, Montpellier, France and D. Cox, Brookhaven National Laboratory, Upton, New York 11973

The Diffraction Anomalous Fine Structure (DAFS) technique combines the short-range selectivity of XAFS with the long-range structural analysis of x-ray diffraction, and provides structural information not available from these techniques alone or in combination. As such, it should throw light on the question of what local atomic arrangements are involved in the scattering that gives rise to the first sharp diffraction peak (FSDP). We have carried out DAFS measurements around the first two diffraction peaks in two typical glasses, GeSe₂ and GeO₂. We discuss the origin of the FSDP and other information that may be drawn about intermediate-range order in the glasses, and prospects for the future use of the DAFS technique in disordered systems.

This work was supported by the U.S. Department of Energy, Materials Sciences, Basic Energy Sciences, under Contract No. W-31-109-ENG-38.