Proton Transfer in Proton Glasses

Abstract

Proton intrabond transfer in Osingle bondH⋯O bonds is the mechanism for dynamic behavior of rubidium/ammonium dihydrogenphosphate mixed crystals. Because of strong proton-proton interactions, such transfer is associated with thermally activated creation of H3PO4-HPO4 intrinsic defect pairs, their hindered diffusion in a random-step fractal potential, and their eventual annihilation. Predictions of a model based on this behavior are compared with determinations on a 35% ammoniated crystal by Courtens of dielectric susceptibility and of relaxation time distribution limits calculated from Brillouin scattering results.