In order to clarify effects such as an increase in the rate of B diffusion in the presence of H or F (and a decrease in the presence of N), total-energy electronic structure calculations were performed for large clusters of atoms that were chosen so as to simulate particular impurity complexes and their reactions. These included a valence-alternation pair which consisted of adjacent 3-fold coordinated N and 1-fold coordinated F (and the corresponding pair in which both N and F were 2-fold coordinated), a valence-alternation pair which consisted of adjacent 3-fold coordinated N and 1-fold coordinated OH, and the corresponding pair which involved 2-fold coordinated O and 2-fold coordinated complexes that included B and N in various configurations.

W.B.Fowler, A.H.Edwards: Materials Science Forum, 1997, 239-241, 33-6