Nj. Sack et Ra. Baragiola, SUBLIMATION OF VAPOR-DEPOSITED WATER ICE BELOW 170-K, AND ITS DEPENDENCE ON GROWTH-CONDITIONS, Physical review. B, Condensed matter, 48(14), 1993, pp. 9973-9978
The sublimation of vapor-deposited H2O ice films was investigated betw
een 60 and 170 K using a piezoelectric microbalance and a mass spectro
meter. The films were grown in vacuum at substrate temperatures betwee
n 30 and 120 K and rates between 0.2 and 7 mum/h. Above 140 K, the sub
limation rate did not depend on the growth conditions tested and yield
ed a sublimation energy of 0.45+/-0.03 eV. Below 140 K, we found that
fresh films have an enhanced sublimation rate, which decays in time an
d which depends on film thickness and growth temperatures. This is att
ributed to sublimation from regions containing amorphous ice, which tr
ansforms with time into the less volatile crystalline ice, with an act
ivation energy of 0.44+/-0.04 eV. The finding of a dependence of subli
mation and crystallization rates on growth conditions can explain larg
e discrepancies in the data published during the last four decades.