AbstractMost studies of Si nanocrystals ion beam synthesized in SiO₂ have shown that a link exists between the observed physical properties and the characteristics of the « populations » of nanoparticles (size-distribution, density, volume fraction). Nevertheless, the direct measurement of these parameters by Transmission Electron Microscopy (TEM) is very difficult and predictive simulations are essential to make the kinetic study complete. This paper presents atomistic simulations aimed at predicting the kinetic evolution of the Si nanoparticles during annealing, taking into account eventual interaction effects. The theoretical results are compared to TEM measurements of the size-distributions observed after high temperature annealing. Experimentally, the growth of these nanoparticles is very slow but their size significantly increases when increasing the initial Si excess. Simulations are in agreement with these experimental results only when taking into account possible interactions between neighboring particles for initial supersaturations larger than 10 at. %.