Bond valence analysis of reverse Monte Carlo produced structural models; a way to understand ion conduction in glasses

Reverse Monte Carlo (RMC) modelling is now widely used for obtaining structural models of amorphous materials that are in quantitative agreement with available experimental structure data. In the case of ion conducting glasses it has been possible to determine the distribution and local environment of the mobile ions. However, only little information has been gained concerning the conduction process in the glasses. In an attempt to at least partly overcome this problem we have applied the bond valence method to reverse Monte Carlo produced structural models of ion conducting glasses. Although we are still not able to directly elucidate the dynamical process, it has been possible to understand experimental conductivity data on a structural basis. In fact, the experimental conductivity and its associated activation energy can be predicted directly from the structural models and conduction anomalies, such as the well-known mixed alkali effect, can be understood using the bond valence approach. Here, we also discuss the possibility of exploring the conduction process in more detail by elucidating the number of available sites for the mobile ions and the dimensionality of the conduction pathways as a function of temperature.