Comment on "energy-loss-spectroscopy studies on the adsorption of hydrogen on cleaved Si(111)-(2×1) surfaces"

In recent energy-loss-spectroscopy studies by Froitzheim, Lammering, and Günter, a new vibrational mode of hydrogen adsorbed on Si(111) surfaces has been found at =100 meV. This new mode was interpreted as a vibration of the hydrogen atom being bonded in a wide bridgelike configuration between two silicon step edge atoms. We suggest that this new vibrational mode could also be the frequency of motion of a hydrogen atom adsorbed at the open site of Si(111). Further, adsorption at this site could be an intermediate step in silane production, erosive action, and formation of SiHx surface complexes. These suggestions are based on the results of our earlier cluster-model study of H/Si(111). © 1983 The American Physical Society.