Eley–Rideal reaction dynamics between O atoms on Beta-cristobalite (100) surface: A new interpolated potential energy surface and classical trajectory study

C.ARASA; V. MORÓN; H.F. BUSNENGO; R. SAYÓS

SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 603 p. 2742 - 2751

0039-6028

We present a theoretical study of the collisions of atomic oxygen with O-precovered Beta-cristobalite (100) surface. We have constructed a multidimensional potential energy surface for the O2/Beta-cristobalite (100) system based mainly on a dense grid of density functional theory points by using the interpolation corrugation-reducing procedure. Classical trajectories have been computed for quasithermal (100–1500 K) and state-specific (e.g., collision energies between 0.01 and 4 eV) conditions of reactants for different O incident angles (hv). Atomic sticking and O2(adsorbed) formation are the main processes, although atomic reflection and Eley–Rideal (ER) reaction (i.e., O2 gas) are also significant, depending their reaction probabilities on the O incident angle. ER reaction is enhanced by temperature increase, with an activation energy derived from the atomic recombination coefficient (cO(hv = 0, T)) equal to 0.24 ± 0.02 eV within the 500–1500 K range, in close agreement with experimental data. Calculated cO(hv = 0, T) values compare quite well with available experimental cO(T) although a more accurate calculation is proposed. Chemical energy accommodation coefficient bO(T) is also discussed as a function of ER and other competitive contributions.