Infrared spectroscopy and ab initio quantum chemical cluster calculations are used to study the decomposition of water on the clean $\mathrm{Si}\mathrm{}\left(100\right)-(2\mathrm{}\times 1)$ surface at low temperature. Using this combined approach we are able to show that the initial surface is actually comprised of an array of isolated and intra-row coupled dimers. The latter are coupled by a hydrogen bonding interaction between OH groups that reside on the same end of adjacent dimers in a dimer row. We find that this interdimer bonding is ∼2 kcal/mol more stable than the isolated dimer case. These findings are postulated to have a significant effect on subsequent oxygen agglomeration.

• Received 10 August 1998

DOI:https://doi.org/10.1103/PhysRevB.58.R13434