Adsorption of Chlorinated Methane Derivatives at the Ice Surface: A Grand Canonical Monte Carlo Simulation Study

Abstract

The adsorption behavior of three chlorinated methane derivative molecules, CH3Cl, CHCl3, and CCl4, is investigated at the (0001) surface of Ih ice at the tropospheric temperature of 200 K by means of grand canonical Monte Carlo simulations. This study completes our earlier investigations concerning the adsorption of CH4, CH2Cl2, and fluorinated methane derivatives. Our results show that neither CHCl3 nor CCl4 exhibits any adsorption. This complete lack of adsorption is attributed to the interplay of the very strong cohesion acting between the adsorbate molecules, and their relatively weak interaction with the ice phase. By contrast, CH3Cl does exhibit a noticeable adsorption on ice, and the adsorbed molecules prefer to turn toward the ice surface by their H atoms, forming weak, C–H····O-type hydrogen bonds with surface waters. The lateral (i.e., adsorbate–adsorbate) contribution to the total interaction energy of the adsorbed molecules is always considerably larger (in magnitude) than in the case of the c...