Surface features on interstellar ice

Abstract

Recent laboratory measurements of near-infrared features arising from dangling bonds at the surfaces of water ice are described. It is argued that the astronomical detection of these features will give a direct measurement of the surface: bulk ratio of interstellar ice, and will constrain several unknown astrophysical parameters, including the rate of H2 formation in dark interstellar clouds, and the extent of large molecule freeze-out on dust by H bonding. These infrared surface features are predicted to have a detectable strength, and should be sought with ISO.