Monte Carlo simulations were developed in order to simulate the aggregation of primary F centers which were created along the path of swift heavy ions. Parameters which were relevant to defect aggregation, as a result of their random hopping, included the migration energy, the temperature in the track, the initial defect concentration and the diffusion time. These were estimated from available experimental data. It was estimated that, in the electronically excited state and at temperatures which increased locally to 1200K, the F centers were sufficiently mobile to make several tens of hops. Most of the F aggregates which formed were extremely small and consisted of only two or three F centers. The fraction of F clusters with more than 10 defects was negligibly small at defect concentrations that were reasonable for ion tracks. Even at the highest initial defect densities, the aggregates were isolated from one another and did not form a percolating trail of defects. Such track morphologies were in good agreement with experimental results.

Modeling of Primary Defect Aggregation in Tracks of Swift Heavy Ions in LiF. E.A.Kotomin, V.Kashcheyevs, V.N.Kuzovkov, K.Schwartz, C.Trautmann: Physical Review B, 2001, 64[14], 144108 (7pp)