Adsorption of triplet O2 on Si(100):: The crucial step in the initial oxidation of a silicon surface -: art. no. 016101

It has long been understood that a precursor mediated chemisorption is a significant part of the dynamics for the adsorption of O-2 on Si(100), which is a much studied model system of surface reaction with considerable technological relevance. However, theoretical studies on the interaction between O-2 and Si(100) have been focused on the excited singlet state of O-2 and unable to explain the observations in surface scattering experiments. We demonstrate by first principles calculations that such a focus is misplaced. In reality, triplet O-2 can also react with Si(100), after overcoming small barriers, and its reaction paths provide a full account for experiments. Our results highlight the important role played by triplet O-2 in surface oxidation.