First-principles molecular dynamics simulations of self-interstitial clusters showed that I2, and the most stable of the I3 clusters, diffused extremely rapidly. In these clusters, the interstitials shared a single bond-centered site. The metastable I3 cluster involved 3 adjacent bond-centered sites. The simulations showed that the 3 interstitials exchanged sites with one another, while the center of the defect remained in the same place. Simulations of I1 and I4 revealed no diffusion on the same time-scale.

Unexpected Dynamics for Self-Interstitial Clusters in Silicon. S.K.Estreicher, M.Gharaibeh, P.A.Fedders, P.Ordejón: Physical Review Letters, 2001, 86[7], 1247-50