Investigation of H-center diffusion in sodium chloride by molecular dynamics simulation

Irradiation of a NaCl crystal with ions leads to the creation of several types of color centers, including F- and H-centers. Since opposed to F-centers, H-centers are mobile at room temperature, their behavior determines the crystal coloration process. Therefore we investigate clustering and migration of H-centers in a NaCl crystal on a 200ps timescale using a molecular dynamics simulation. The clustering is measured and mostly occurs in the first 20 ps of the simulation. The clusters are not seen to migrate through the lattice. Non-clustered H-centers are mobile, but do not seem to have a clear directional diffusion on this timescale.