Figure 6: Stages of proton diffusion.

Schematic representation of the phonon-assisted hydrogen diffusion process in a long range chain of oxygen. (a) Oxygen lattice with no protons. (b) Local relaxation of oxygen ions when a proton-polaron is incorporated. (c) Proton rotates around the oxygen to a new position. (d) The new proton position adjusts the oxygen lattice relaxation. (e) Proton hops to the next oxygen site.