CHEMICAL EFFECTS ON THE FREQUENCIES OF SI-H VIBRATIONS IN AMORPHOUS SOLIDS

We show that the frequencies of the bond-stretching vibrations of Si-H groups in amorphous solids, such as a-Si and a-SiO2, vary systematically with the electronegativities of the next nearest neighbor atoms of the network. This induction effect is well-known in substituted silane molecules, SiHR1R2R3; however, this represents the first discussion of a similar effect in network solids. The empirical relationship developed for the vibrational frequencies in the silane molecules is shown to apply to the solid state network structures as well. The applicability of this analysis to other network amorphous solids is illustrated by comparing the vibrational frequencies of the P = 0 bond in molecules, 0 = PR1R2R3, and network glasses, e.g., a-P2O5, and a-P2O5-SiO2. © 1979.