A first-principles study was made of the E1’ defect in -quartz, and of the analogous E’ defect in amorphous SiO2. The results of the calculations supported the suggestion that both of these defects were positively charged O vacancies. The ground-state configurations of the defects were characterized by a large local relaxation, of the atomic structure, which led to localization of the unpaired electron on a Si dangling bond. The results explained both the strong and weak features that were observed in experimentally determined spectra.

M.Boero, A.Pasquarello, J.Sarnthein, R.Car: Physical Review Letters, 1997, 78[5], 887-90