Anharmonic Decay of Vibrational States in Amorphous Silicon

Anharmonic decay rates are calculated for a realistic atomic model of amorphous silicon. The results show that the vibrational states decay on picosecond time scales and their decay rates increase with increasing frequency. These results disagree with a recent experiment. In contrast to predictions of the fracton model, we find no evidence that the anharmonic decay is inhibited in the region of localized states.