Abstract
Random pairing simulation and low temperature scanning tunneling microscopy (STM) are used to investigate the detailed O 2 dissociative adsorption processes at 200 K for various coverages. The distribution of oxygen adatoms shows a strong repulsion between the adsorbates with a radius of ∼0.8 nm. The comparison between STM results and simulation reveals two prominent pairing distances of 2 and 4 nm and their branching ratio is about 2:1. These findings shed new light on the origin of the large intrapair distances found and on the process behind the empirical "eight-site rule." © 2009 American Institute of Physics.