Molecular dynamics and Monte Carlo simulations of organic compounds adsorbed on ice surfaces
Résumé
The adsorption characteristics of small, partially oxidized hydrocarbons, such as methanol, formaldehyde, ethanol and acetic acid molecules on an ice Ih(0001) proton disordered crystal have been studied on the basis of computer simulations performed at tropospheric temperatures. Molecular dynamics simulations as well as Grand Canonical Monte Carlo calculations have been performed to determine the configurations of the molecules in their adsorption sites, the adsorption energies, the saturation coverage of one monolayer above the ice surface, and the corresponding adsorption isotherms. The results of these simulations are in close agreement with experimental data, and demonstrate that the main driving force for the adsorption of these partially oxidized hydrocarbons on ice is the formation of hydrogen bonds, not only with the water molecules of the ice surface, but also within the adsorbate.