The energy landscape of an α-quartz O vacancy in the lowest triplet state was investigated. Four local minima were identified and geometries, total energies, and electron paramagnetic resonance parameters were obtained. On the basis of calculated values for the magnetic dipole interaction between the electrons, 2 of the structures were identified with known triplet centers detected by electron paramagnetic resonance. The effect of Ge substitution was studied, and it was concluded that Ge impurities in silica acted as traps for dangling bonds with a trapping energy of about 1.5eV relative to Si ions.

Triplet States at an O Vacancy in α-Quartz. J.Lægsgaard: Physical Review B, 2002, 66[2], 024107 (9pp)