Solitons Coming Alive in Surface Proton Conduction

Solitons Coming Alive in Surface Proton Conduction 

The majority of studies of collective proton motion in ice or at interfaces resorted to model systems represented by infinite quasi-one-dimensional hydrogen-bonded chains (Gordon, 1990 Pnevmatikos, 1988 Tsironis and Pnevmatikos, 1989 Weiner and Askar, 1970). The chain consists of two coupled sublattices of alternating mobile protons and heavy anions. Each mobile proton is located between a pair of heavy anions, referred to, as before, as SGs. SGs are considered to be fixed with their tail group but their anionic head groups are allowed to fluctuate about their equilibrium positions. They act as proton relay groups. 

Mobile protons could be transferred in two types of motions (1) Protons could rattle back and forth between symmetric minima of the effective substrate potential energy. The minima are located at hydrogen bond distance from either of the two neighboring SGs. The double well potential, experienced by the intermittent proton, depends on the equilibrium separation of SGs and on their fluctuations. Similar to what happens in the formation of a Zundel ion in water, the double well potential may transform into a single well potential upon close approach of neighboring SGs. Spontaneous symmetry-breaking, associated with these proton motions, leads to the 

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