Structural determination for H2O adsorption on Si(001)2 × 1 using scanned-energy mode photoelectron diffraction

Using scanned-energy-mode photoelectron diffraction we have determined the local adsorption geometry of the OH fragments adsorbed on Si(100)(2 × 1) surface. On this substrate water is known to adsorb dissociatively even at low temperature (90 K), which gives rise to a surface layer comprising coadsorbed OH and H species. The OH fragments are found to be adsorbed in off-atop sites at a dimerised surface Si atom with Osingle bondSi bond-lengths of 1.7 ± 0.1Å and bond-angles relative to the surface normal of 22 ± 5°.