Influence of the surrounding environment on the structural and optical properties of oxygen-deficient centers in pure and Ge-doped silica: an ab initio study.

Abstract : We calculated the structural and optical absorption bands of oxygen-deficient centers (ODC) in pure and Ge-doped silica using a condensed matter ab initio formalism. We used a statistical approach to simulate the defect properties in the various surrounding environments offered by our 108 atoms supercell. In this paper, we show that there exists bivariate correlations between the Si-Si bond distance of the ODC and the formation energy or the wavelengths of absorption bands of the defects. But if this structural property dominates the local effects, it is in competition with long-ranged effects explained by the viscous character of the surrounding matrix.