Semiempirical calculation of the peroxide bridge in glassy silicon dioxide

The characteristics of a peroxide bridge are studied by the quantum-mechanical semiempirical method MPNDO/3 in the model of a molecular cluster. The geometry of the cluster was optimized for different distances between silicon atoms. The coordinates of the two oxygen atoms forming the peroxide bridge were employed as the optimization parameters. The minimum total energy of the cluster was sought. The scheme of single-electron levels was found. The effect of the peroxide bridge on the electronic structure of v-SiO₂ reduces to splitting of shallow levels from the edges of allowed bands, corresponding to strongly localized states. The energy of formation of a cluster in the presence of a peroxide bridge is close to the energy of formation of a cluster without defects.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 35–38, April, 1987.The authors thank Professor V. L. Bonch-Bruevich and the participants of his seminar at Moscow State University for their interest in this work and for useful discussions.