Structural characterization of water ice condensed on silicate grains by infrared and Raman spectroscopy

Abstract

The sticking and nucleation properties of gas-phase molecular species are influenced by the properties of the substrate, including its chemical and physical characteristics. The chemical reactivity that occurs in ice layers during thermal and irradiation events can also be affected by these properties. The spectroscopic properties of two magnesium silicate minerals, forsterite and enstatite, were investigated by infrared and Raman spectroscopy and Density Functional Theory calculations. The effect of structural properties on the condensation of water ice on top of the mineral grains was analyzed by Raman microscopy. The spectroscopic characterization of the silicates agrees quite well with the computational results, and the modeling of the ice layers on top of the grains describes the spectroscopic signature obtained by Raman microscopy very successfully. The information obtained enhances our understanding of the interface of ice and dust in astrophysical environments.