Using a conceptually simple, quasi-adiabatic,
fast scanning calorimetry
technique, we have investigated the sublimation kinetics of ice films
with thicknesses ranging from 14 to 400 nm at environmentally relevant
temperatures, between 223 and 268 K. The technique enables accurate
determination of ice sublimation rates into vacuum under the conditions
of free molecular flow during rapid yet quasistatic heating. The measured
sublimation fluxes yield the vapor pressure of the ice samples, which
is indistinguishable from that derived from experiments under near-equilibrium
conditions. Thus, in agreement with the microscopic reversibility
principle, we conclude that the mass accommodation coefficient of
water by ice is unity and temperature-independent in the temperature
range of the studies. We discuss these findings in the context of
current computational and theoretical research into the chemistry
and physics of aqueous interfaces.