Proton mobility in thin ice films: a revisit

We have examined proton transport through an ice film in the temperature range 73-140 K by initially adding hydronium ions into the interior of the film and then monitoring the build-up of hydronium ion population at the film surface. The result confirms that the proton exhibits limited mobility in the ice film at low temperature, but it becomes highly mobile at temperature above 130 K. Based on this result we suggest an explanation of the anomalous experimental observations in the literature for the proton mobility in ice films.