Calculation of the g-tensor and 29Si hyperfine tensors of the E′1 centre in silicon dioxide

Both the g-tensor and the tensors of 29Si hyperfine interactions are calculated for the model of an O− vacancy in α-quartz with asymmetric lattice distortion proposed by Yip and Fowler to explain the E′1 centre in SiO2. The extended Huckel theory (EHT) is applied to an α-quartz cluster. The dangling bonds of the outer atoms are saturated by hydrogen. Theoretical and experimental results agree quantitatively well. Similar calculations are performed for the analogous model in β-cristobalite. Computations with and without consideration of Si3d functions are compared.