We present the first tight-binding molecular dynamics simulation of hy
drogen diffusion in silicon for 800 < T < 1800 K. We show that the dif
fusion law deviates from the high-temperature Arrhenius plot below T =
1200 K, and we compute the diffusion coefficient in a region where no
experimental data are available. The diffusion mechanism and path are
observed during very long simulations. We demonstrate that hydrogen d
iffuses through jumps, avoiding low valence-charge-density regions. Ob
servation of jumps between non-nearest-neighbor bond-center sites is r
eported, and the role of the phonon spectrum of silicon is discussed.