Comparative Study of the Adsorption of 1-and 2-Propanol on Ice by Means of Grand Canonical Monte Carlo Simulations

In this paper, we use Grand Canonical Monte Carlo simulations to compare the adsorption characteristics of two propanol isomers (1-and 2-propanol) on crystalline ice, at the temperature of 227 K (i.e., typical of the Earth's troposphere), for which experimental data are available in the literature. The adsorption isotherms simulated for these two isomers show a very good agreement with the reported experimental data, giving thus confidence in the two interaction potential models used in the calculations. The results of the simulations thus nicely support the experimental conclusion that 2-propanol is preferentially adsorbed on ice with respect to 1-propanol, at least in the low pressure range where only a few molecules are trapped by the ice surface. The accuracy of the approach used, as tested here in tropospheric conditions, opens the way for its use in modeling studies also relevant to astrophysical context.