Classical molecular dynamics simulations were used to study the dynamics of Na atoms in amorphous samples. It was found that the Na trajectories formed a well-connected network of pockets and channels. Within these channels, the motion of the atoms was non-cooperative and was instead achieved via independent thermally activated hops of individual atoms between pockets. By determining the probability that an atom returned to a given starting site, it was shown that such events were not important for the dynamics of this system at high temperatures.

Channel Diffusion of Sodium in a Silicate Glass. P.Jund, W.Kob, R.Jullien: Physical Review B, 2001, 64[13], 134303 (5pp)