Pseudopotential  ab initio  local density approximation methods were used to create and study super-cells which contained 82 Si atoms and between 5 and 7 H atoms. In particular, energies and structural properties were obtained for H, in various charge states, that passivated dangling bonds in bond-centered positions and in other interstitial sites. The most striking result which was found was a rather large (of the order of 1eV) spread of energies for a given type of defect; depending upon its surroundings. It was also found that changes in the single-particle energies, or energy eigen-values, from defect to defect were not very close to changes in the total energy. Thus, the distinction between bond-centered H, and a dangling bond plus a Si-H bond, was not as clear as expected. The calculations also provided some insight into possible migration mechanisms and activation energies for H movement.

P.A.Fedders: Physical Review B, 1995, 52[3], 1729-37