Theoretical Dynamics Study of Atomic Oxigeno ver Beta-Cristobalite(100).

C. ARASA, H.F. BUSNENGO, A. SALIN Y R. SAYÓS

San-Petesburgo, Rusia

Simposio; 25th Internacional Symposium on Rarefied Gas Dynamics; 2006

In this work we examine the interaction of O(3P) atoms with â-cristobalite (100) surface. We derived a potential energy surface for the ground O/SiO2 state based in density functional theory calculations along with some empirical data. We study the adsorption and reflection dynamics considering a 9-layer slab (2x2) cell coupled to several generalized Langevin oscillators to control the surface temperature (TS). We obtained high adsorption probabilities (85-98%) in comparison with reflection at all initial conditions, which also decrease slightly when O kinetic energy or TS are augmented. Adsorption processes correspond to a rapid O sticking over Si first-layer sites of â-cristobalite (100) surface. Our calculated thermal initial sticking coefficients are much bigger than indirect values used in some published kinetic models about O recombination reactions on other type of silica surfaces.