title: Recombination and chemical energy accommodation coefficients from chemical dynamics simulations: O/O2 mixtures reacting over a β-cristobalite (001) surface.
abstract: A microkinetic model is developed to study the reactivity of an O/O(2) gas mixture over a β-cristobalite (001) surface. The thermal rate constants for the relevant elementary processes are either inferred from quasiclassical trajectory calculations or using some statistical approaches, resting on a recently developed interpolated multidimensional potential energy surface based on density functional theory. The kinetic model predicts a large molecular coverage at temperatures lower than 1000 K, in contrary to a large atomic coverage at higher temperatures. The computed atomic oxygen recombination coefficient, mainly involving atomic adsorption and Eley-Rideal recombination, is small and increases with temperature in the 700-1700 K range (0.01 < γ(O) < 0.02) in good agreement with experiments. In the same temperature range, the estimated chemical energy accommodation coefficient, the main contribution to which is the atomic adsorption process is almost constant and differs from unity (0.75 < β(O) < 0.80).
authors.affiliation: Departament de Química Física and Institut de Química Teòrica i Computacional, Univ. Barcelona, C. Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Morón
authors.forename: Pablo
authors.initials: P
authors.lastname: Gamallo
authors.forename: Ludovic
authors.initials: L
authors.lastname: Martin-Gondre
authors.forename: Cédric
authors.initials: C
authors.lastname: Crespos
authors.forename: Pascal
authors.initials: P
authors.lastname: Larregaray
authors.forename: Ramón
authors.initials: R
authors.lastname: Sayós
mesh_terms: D007700:Kinetics; D056004:Molecular Dynamics Simulation; D010100:Oxygen / Q000737:chemistry*; D011789:Quantum Theory; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D012822:Silicon Dioxide; D010100:Oxygen