A study was made of the structural and dynamical characteristics of the Na atoms inside and outside the so-called diffusion channels in glassy Na2O-4SiO2 by using classical molecular dynamics. It was shown that on average neither energetic arguments nor local environment considerations could explain the increased density of Na atoms inside the subspace made of the channels. Nevertheless, it was shown that at low temperature the mean-square displacement of the Na atoms inside this subspace was significantly larger than that of the atoms outside the channels.

Characterization of Channel Diffusion in a Sodium Tetrasilicate Glass via Molecular-Dynamics Simulations. E.Sunyer, P.Jund, R.Jullien: Physical Review B, 2002, 65[21], 214203 (5pp)