A numerical simulation of the composition modification induced in ZnSe by nanosecond irradiation of the KrF excimer laser (lambda = 248 nm, tau = 20 ns) has been carried out. Intensive evaporation of components has shown to results in the material surface cooling and forming a nonmonotone temperature pro. le with maximum temperature in semiconductor volume at the distance of similar to 6 nm from the surface. As a result of evaporation and diffusion of components formation of the near-surface layer with nonstoichiometric composition takes place and enrichment of selenium reaches maximum value not on the surface, but in the semiconductor volume. (C) 2008 Elsevier B. V. All rights reserved.