Extensive simulations of a-Si:H were performed by using the ab initio Sankey-Drabold code. The super-cells contained some 70 atoms, and only one defect, in order to minimize defect-defect interaction. Simulations of super-cell samples that originally contained one bond-centered H in an otherwise defect-free sample exhibited bond-center to bond-center diffusion as in c-Si. However, localized motion of defects and H atoms was also observed at a very fast time-scale.

Study of Local and Extended Migration of H and Defects in a-Si by Molecular Dynamics Simulations. Fedders, P.A.: Materials Research Society Symposium - Proceedings, 1996, 420, 521-5