Adsorption of H2O2 at the surface of Ih ice, as seen from grand canonical Monte Carlo simulations

Abstract

Adsorption of H 2 O 2 at the (0001) surface of I h ice is investigated by GCMC simulations under tropospheric conditions. The results are in qualitative agreement with experimental data and reveal that the main driving force of the adsorption is the formation of new H 2 O 2 -H 2 O 2 rather than H 2 O 2 -water H-bonds. The isotherm belongs to class III and not even its low pressure part can be described by the Langmuir formalism. At low coverages H 2 O 2 prefers perpendicular alignment to the surface, in which they can form three H-bonds with surface waters. At higher coverages parallel alignment, stabilized by H-bonds between neighbouring H 2 O 2 molecules, becomes increasingly preferred.2

Adsorption of Methylene Fluoride and Methylene Chloride at the Surface of Ice under Tropospheric Conditions: A Grand Canonical Monte Carlo Simulation Study

“…Indeed, the GCMC method has been successfully applied to calculate the adsorption isotherms of water and other small molecules at various different solid surfaces, such as at carbonaceous materials, 15-23 self-assembled monolayers, 24,25 covalent organic frameworks, [26][27][28] protein crystals, 29 metal oxides, [30][31][32][33] zeolites, [34][35][36][37][38][39][40][41] kaolinite, [42][43][44] and ice. [45][46][47][48][49][50][51][52][53] Further, besides the adsorption isotherms themselves, the structure and energetics of the adsorption layer can also be analyzed in detail in such simulations. However, we are not aware of any simulation or other theoretical studies (e.g., ab initio calculations) of the adsorption of halogenocarbon molecules at the surface of ice.…”

Adsorption of Methylamine at the Surface of Ice. A Grand Canonical Monte Carlo Simulation Study

“…[23][24][25][26][27][28][29][30][31][32] In addition, Grand Canonical Monte Carlo (GCMC) simulations 17,33 have also been performed to simulate the adsorption isotherms of various classes of volatile organic compounds and atmospheric pollutants on ice at low temperatures. [34][35][36][37][38][39][40][41][42][43][44] Indeed, the GCMC method is particularly suitable for studying adsorption, because in this method the chemical potential rather than the number of the adsorbate molecules is fixed in the simulation. As a consequence, by systematically varying the value of this chemical potential in a series of GCMC simulations, and determining the number of the adsorbed molecules per surface unit as a function of this, the adsorption isotherm can be calculated directly, from extremely low pressures up to the point of condensation.…”

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

“…Monte Carlo simulation on the grand canonical (μ,V,T) ensemble is a particularly suitable tool for calculating adsorption isotherms on ice by controlling the chemical potential and, thus, the partial pressure, of the adsorbed molecules. Therefore, series of GCMC simulations have been performed at 200 K, i.e., a temperature relevant for the upper troposphere, for various trace gases [25,[27][28][29]31,35,37,[40][41][42][43]44,46,47], aiming at comparing their ability to bind to the ice surface. Lower temperatures down to 20 K, typical of the interstellar medium, have also been considered in the case of methylamine adsorbed on amorphous ice [45], to characterize the behaviour of this precursor of glycine, an amino acid, which is of particular interest in astrochemical research because it is related to the formation of prebiotic molecules [15].…”

“…Thus, for more than 15 years, we have developed numerical simulations to investigate the adsorption of trace gases, especially organic molecules, on ice surfaces under tropospheric, and more recently, interstellar, conditions. Then, in a series of previous papers, we used molecular dynamics (MD) and/or Monte-Carlo (MC) simulations to model, at the molecular scale, the interaction between ice and various alcohols (methanol [24,25], ethanol [26]), aldehydes (formaldehyde [24,27], acetaldehyde [28], benzaldehyde [29]), carboxylic acids (formic [30,31], acetic [32], oxalic [33] acids), ketones (acetone [34,35], hydroxyacetone [36]), aromatic molecules (benzene [37], naphthalene [37], anthracene [37], phenanthrene [37,38], benzaldehyde [29]), halogenated methane derivatives [39][40][41][42][43], methylamine [44,45], hydrogen peroxide [46], and hydrogen cyanide [47]. We also simulated the trapping of various atomic and molecular species into clathrate hydrates in the astrophysical context [48][49][50].…”