HALL EFFECT ON PROTONS IN ICE

Surface conductivity has to be taken into account for a successful Hall-Effect measurement in ice. Bulk and surface currents have been determined separately by guard-electrode techniques. The apparent thermal activation energy of the bulk conductivity is ∼ 8,5 kcal/mole. Published values are invariably higher. This can be explained by the strong temperature dependence of surface currents. A contribution due to surface currents has to be considered above -20°C. By taking into account the influence of surface conductivity it has now proved possible to detect and to measure the Hall-Effect in ice. A positive sign of the Hall coefficient was found. This result provides evidence for a protonic mobility considerably higher than the mobility of OH--ions. The mobility decreases with increasing temperature. The value is 1,4 cm2V-1sec-1 at -8°C. The relatively high value of the mobility seems to indicate that the proton cannot be considered as a quasi-free charge carrier. A simple model characterizes the conductivity mechanism in terms of the time of correlated proton jumps across several H-bonds, the time between consecutive jumps, and the effective mass. © 1968 Springer-Verlag.