Molecular dynamic modelling of potassium transport in a potassium-silicate glass irradiated by fast electrons

The binary potassium-silicate glass has been prepared from an ionic liquid by molecular dynamics (MD) using 900 ions interacting via Born-Mayer type pair potentials. The standard MD procedure was adapted so that an electric field and/or momentum transfer, corresponding to the elastic scattering of primary electrons, could be applied to a particular set of ions. Results have shown that the electric field itself should cause dielectric breakdown to drive the ions out of their sites. If the electric field is accompanied by momentum transfer from the primary electron, then potassium ions can be released from their sites and can be further driven by the macroscopic electric field, created by trapped electrons in the glass. The depth and width of the potassium potential well has been estimated by studying the motion of ions in a high electric field. (C) 2001 Elsevier Science B.V. All rights reserved.