Localized adatom vibrations in Si clusters

Abstract
We present results for the vibrational spectra of models for Si clusters. Our calculations are based on the Stillinger-Weber phenomenological potential. We find that in a 33-atom model cluster there exist localized ‘‘adatom’’ vibrations that are similar in character to modes of the 7×7 reconstructed Si(111) crystalline surface. The unique character of the localized adatom modes would serve as a stringent test of the cluster geometry through Raman experiments.