Surface Science Letters On the role of long-range elastic interactions for the Al(1 1 1) oxide nucleation kinetics

We present a simple kinetic model for chemisorption and oxidation kinetics on Al(1 1 1). The novel feature of the model is that it combines the correct (experimental) adsorption kinetics (as manifested in experimentally measured O island size distributions), with a model including short-range nn attractive and long-range repulsive interactions between adsorbed O atoms. The latter interaction is a consequence of the strain in a substrate caused by forces due to the presence of chemisorbed O atoms. The combination of these two interactions is essential, since it influences the place exchange jump rate, which in turn is the controlling step for oxide nucleus formation in the model. The predictions of our Monte Carlo simulations, based on the transition state theory include: (i) a threshold in chemisorbed oxygen coverage for oxide formation, (ii) total oxygen uptake kinetics, (iii) oxide uptake kinetics and (iv) appearance of place exchange events for small O islands (down to a monomer size), depending on the island environment. Our predictions for (i–iii) are in excellent agreement with experimental results for a unique choice of model parameters. � 2003 Published by Elsevier B.V.