Isotope effect on the migration of protons in NH<inf>4</inf>Cl and NH<inf>4</inf>Br crystals

Excess electrical conductivity is induced by plastic deformation in NH4Cl, NH4Br, ND4Cl and ND4Br crystals. The annealing of the excess conductivity is fitted to a monomolecular decay characteristic of protons and deuterons. The relaxation parameters are examined in the light of existing theories of isotope effect in mass transport. Values of 0.96 and 0.93 are deduced for g, the fraction of kinetic energy possessed by the jumping ion at its saddle point. © 1976.