Interpretation of structural data on superionic conductors in terms of thehindered-rotation diffusion model

The degree to which the ratio between the characteristic times of ionic mot ion (time of rest/time of flight) controls the choice between the jump and continuous diffusion models in the interpretation of structural data on sup erionic conductors is discussed. A consideration of the short-range order a nd the dynamic characteristics of the beta-AgI structure studied by EXAFS i s augmented by a qualitative picture of atomic displacements in alpha-AgI d educed from the symmetry rules. The relative intensities of the Debye peaks in the X-ray patterns of several superionic conductors (AgI, Ag3SI, and Ag 2Se) are refined.