MULTINUCLEAR AND MULTIDIMENSIONAL NUCLEAR-MAGNETIC-RESONANCE INVESTIGATION OF SILVER-IODIDE SILVER PHOSPHATE FAST-ION CONDUCTING GLASSES

The results of a multi-nuclear nuclear magnetic resonance (NMR) study of (AgI)(x)(Ag2O)(y)(P2O5)(1-x-y) glasses are reported. Using the two- dimensional variable-angle correlation spectroscopy experiment, the is otropic and arisotropic chemical shift interactions of phosphorus were determined as a function of silver iodide and silver oxide compositio n. From these measurements we determine the average conformation of th e phosphate groups. In addition, the Ag-109 NMR spectra were recorded, as a function of both composition and temperature. At high silver oxi de concentrations, interaction between the silver and phosphate groups has been detected, but in glasses in the series the (AgPO3)(x)(AgI)(1 -x) P-31 NMR is strikingly independent on the silver iodide compositio n. The temperature dependence of the silver NMR linewidths in these sy stems shows clearly the silver mobility, and at lower temperatures no evidence for multiple distinct silver binding sites was observed. The silver chemical shift is strongly dependent on both composition and te mperature. The former effect is interpreted in terms of the influence on the chemical shift of binding to oxygen versus iodine.