${\mathrm{H}}_2$O chemisorption on Si(100) is studied with high-resolution infrared spectroscopy. Water molecules are found to dissociate upon room-temperature exposure forming Si-H and Si-OH. Mild annealing breaks up the O-H molecule resulting in oxide, monohydride, and dihydride species. The angle made by the effective dynamic dipole moment associated with the Si-H bond, with respect to the surface normal, is measured for the different hydrides formed.

• Received 31 October 1983

DOI:https://doi.org/10.1103/PhysRevB.29.3677