Quantitative determination of the adsorption site of the OH radicals in the (formula presented) system

Abstract

Using scanned-energy mode photoelectron diffraction from the O (formula presented) level, the local structure around the adsorbed OH species resulting from the interaction of (formula presented) with a (formula presented) has been determined, by a combination of direct data inversion using a “projection” method and multiple-scattering simulations. The O atom is bonded to a surface Si atom with a Si-O bond length of (formula presented) the Si-O bond being tilted away from the surface normal by (formula presented) This bonding Si atom is at one end of a surface dimer, which lies parallel to the surface to within ±9°, but there appears to be a lateral offset of the dimer along the dimer direction away from the fully symmetric position by approximately 0.3 Å, possibly reflecting a residual asymmetry associated with the adsorbate bonding. The main structural parameters are in excellent agreement with the results of a previously published density-functional theory slab calculation. © 2002 The American Physical Society.