Molecular-scale simulations of organic compounds on ice: application to atmospheric and interstellar sciences. Molecular-scale simulations of organic molecules adsorbed on ice: application to atmospheric and interstellar sciences

International audienceIn this paper, we present a brief review of what has been learned about the adsorption characteristics of various organic molecules at the surface of ice, from more than 15 years of computer simulation studies at the molecular scale. In particular, grand canonical Monte Carlo and molecular dynamics calculations were performed to determine the adsorption isotherms, the saturation coverage of the first molecular layer at the ice surface, the preferred orientations of the molecules in their adsorption sites, and the corresponding adsorption energies. The results of the simulations indicated that the main driving force for trace gas adsorption on ice is hydrogen bonding not only between the adsorbate and the water molecules of the ice surface, but also within the adsorbate. When possible, the comparison with available experimental data showed a close agreement, supporting thus the methodology used in the modelling. Finally, the present review demonstrates how computer simulation can nicely complement experimental approaches for studying interactions between trace gases and ice under tropospheric and interstellar conditio