The femtosecond time-resolved spectroscopy, of defect formation that was promoted by valence-electron excitation in halide crystals, was reviewed. Firstly, the characteristics of the various transient relaxed configurations of electron-hole pairs or excitons, which played important roles in the defect formation process, were summarized. The results for the self-trapping of holes in this material were then described with regard to the specific features that were revealed by femtosecond spectroscopy. The dynamics of Frenkel pair formation in alkali halide crystals were considered on the basis of results for various crystals at temperatures ranging from 5 to 300K. Emphasis was placed on new features of the damage mechanism which arose during lattice relaxation of the localized electron-hole pairs.

K.Tanimura, H.Fujiwara, T.Suzuki: Nuclear Instruments and Methods in Physics Research B, 1996, 116[1-4], 26-32