The structure of amorphous Na₂O:ZnO:3SiO₂

The structure of the system Na₂O:ZnO:3SiO₂ has been studied using the molecular dynamics (MD) computer simulation technique. An empirical form of a modified Born-Mayer-Huggins (BMH) potential energy function was used to describe the interactions between atomic pairs. Calculated pair distribution functions (PDFs) and near-neighbor coordination number data from the MD simulations are in good agreement with EXAFS data. The results indicate the existence of mainly SiO₄ and ZnO₄ tetrahedra bonded at corners to form an amorphous network. However, areas of the simulated glass which were rich in ZnO were found to accommodate zinc in octahedral coordination. The local near-neighbor structure of the glass was determined to be similar to its crystal analog, disodium zincosilicate.