First-principles total-energy calculations were performed which clarified the stable structures of B, and the mechanisms of B diffusion in SiO2. It was found that a B atom adopted various stable and metastable geometries; depending upon its charge state. It was also found that atomic rearrangements during diffusion revealed a wealth of bonding possibilities in SiO2, and that the calculated activation energy agreed with the experimental data available.

Theoretical Study of Stable Structures and Diffusion Mechanisms of B in SiO2. M.Otani, K.Shiraishi, A.Oshiyama: Applied Surface Science, 2003, 216[1-4], 490-6. See also: Physica B, 2003, 340-342, 949-52