Theoretical Study of O[sub 2] Dissociation and Reflection on the β-Cristobalite (100) Surface

Abstract

In this theoretical study we investigate the interaction of molecular oxygen with β‐cristobalite (100) surface, which is based in an ab initio interpolated full dimensional potential energy surface (PES) built from 2000 DFT points by using the Corrugation Reducing Procedure. This PES has been previously used to study the atomic oxygen recombination (Eley‐Rideal reaction) over the same solid. We study the dissociative sticking and the reflection dynamics over the silica slab at different surface temperatures (Ts). Quasiclassical trajectories are computed for both thermal and state‐specific reactants (Ts = 100–1100 K). O2 reflection is the main process at thermal conditions (>98%) although molecular absorption (diffusion) is also observed. Normal incidence collisions favor this molecular absorption. O2 translational and vibrational excitation considerably enhances the molecular dissociation, contrary to rotational excitation. The high surface corrugation and PES anisotropy allows understanding this behavior and the extension of the different channels.