Heterogeneous nucleation of oxygen on silicon: Hydroxyl-mediated interdimer coupling on Si(100)-(2x1)

Infrared spectroscopy and nb initio quantum chemical cluster calculations are used to study the decomposition of water on the clean Si(100)-(2 x 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 similar to 2 kcal/mol more stable than the isolated dimer case. These findings are postulated to have a significant effect on subsequent oxygen agglomeration. [S0163-1829(98)52944-X].