Kinetics and dynamics of molecular oxygen adsorption on Ru(001), and reaction dynamics of gas-phase atomic oxygen on precovered Pt(111) Ir(111), and Ru(001) surfaces.

摘要

Surface science provides many tools and techniques to study the fundamental processes involved in heterogeneous catalytic reactions. One extremely useful technique for determining adsorption probabilities is the reflectivity measurement in which the background signal for a species is monitored using a mass spectrometer while exposing a surface to a molecular or atomic beam.;In the current work, reflectivity measurements are used to measure the initial dissociative chemisorption probability (S;Modified reflectivity measurements are also used to study the interaction of O-atoms with adsorbate precovered surfaces. The initial probability that an impinging O-atom induces the desorption of molecular oxygen on Pt(111) is directly measured, and compared to previously published results that were calculated from product time-of-flight velocity distributions. An unexpected effect of incident angle is observed, and a mechanism involving the exchange of O-atoms with adsorbed molecular oxygen is quantified.;Finally, the probability of CO