The correlation between the local structure of an alkali glass and its ionic conductivity was investigated by means of a bond-valence analysis of reverse Monte Carlo fits to experimental diffraction data. A previously detected general relationship between the volume fraction of the transport pathways, and their ionic conductivity, also permitted reproduction of the mixed alkali effect and provided further insight into its structural origin. A sharp drop in the conductivity was due mainly to blocking by immobile unlike cations; which was very effective, because of the low dimensionality of the pathways at local length-scales. Evolution of the transport pathways in time was studied by applying the bond valence approach to entire molecular dynamics trajectories.

Structure Conductivity Correlation in Reverse Monte Carlo Models of Single and Mixed Alkali Glasses. S.Adams, J.Swenson: Solid State Ionics, 2004, 175[1-4], 665-9