Eley-Rideal and Langmuir-Hinshelwood Recombination Coefficients for Oxygen on Silica Surfaces

The energetics and dynamics of the Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) recombination reaction of oxygen atoms on β cristobalite have been studied within a semiclassical collisional model. The calculated recombination coefficient γ for the E-R reaction at T s = 1000 K is in satisfactory agreement with the experimental value, whereas at T s = 600 K a satisfactory agreement is found between the L-H γ value and the experimental one. Results on the energy exchanges between the formed O 2 molecules and the silica surface are reported. Site-specific effects as well as the influence of the top layer surface structure are also pointed out and discussed.