The electronic states of AgI-based superionic conducting glasses were calculated by using the DV-Xα cluster method. The calculations were carried out for the AgI4 tetrahedral unit. The net charge on the Ag ion in the AgI4 cluster was found to be about 0.08; which was smaller than that on the Na ion (0.39) in the NaI4 cluster. However, the bond order between Ag and I ions was almost the same as that between Na and I ions in the NaI4 cluster. This suggested that the total interaction between Ag and I ions, including both ionic and covalent bonding in the AgI4 cluster, was smaller than that between Na and I ions in the NaI4 cluster. This characteristic electronic state of the Ag ion was one of the causes of rapid Ag-ion movement in AgI-based glasses.

Y.Kowada, H.Adachi, M.Tatsumisago, T.Minami: Journal of Non-Crystalline Solids, 1998, 232-234, 497-501