Figures display a sequence of images that illustrate an instance of proton hopping. Proton hopping commonly occurs along Grotthuss chains (GC). The concept of GCs was first introduced by Achar et al. and was used in analyzing PT in SSG. We define a GC as a hydrogen bonded sequence of three or more OH groups, within which protons can move in either direction without any OH rotations. The teal H atoms in Figures constitute the GC at that given time span of the simulation. Proton transport over long distances can only take place if GCs break and form new GCs that traverse different regions of the surface. Breaking of GCs requires the rotation of OH groups. Protons can then percolate through the 2-D surface of DSG. Plots of the CEC trajectories (unwrapped Cartesian coordinates) are superimposed as a single plot in Figure . The darkness of red indicates that CECs have traversed more frequently through that region. Trajectories from 50 DP-MD simulations were used to generate this plot.