There is various other important kinetic, electronic and impurity-complex related information that is relevant to this work. The initial total TD formation rate at 450C is proportional to [Oi]n, n=4  initially suggesting early TDs contained 4 O atoms; later work has shown this to be a function of both [Oi] (for [Oi] cm-3 n was close to 1), and temperature. At lower temperatures (T 400C) n=2, and this increases at 450C to n=4 as seen earlier. This suggests that at lower temperatures, oxygen dimerisation is the rate dominating step, but at higher temperatures this is replaced with simple Oi diffusion. At 500C, n increases further.
Uniaxial stress measurements on the electronic IR absorption associated with the TDs has also allowed symmetry assignments. This also showed C2v symmetry [244,245], with the effective-mass like donor state constructed from a single pair of conduction band valleys  along  . The C2 axis is compressive and lies along  .