Abstract
Metastable relaxed excitons created by pulsed electron irradiation in alkali-halide crystals are excited to higher states by a laser pulse. Consequent changes in excitonic absorption and emission yield data on triplet-singlet conversion and on polarization of the optical transitions. It is found that F centers are formed upon promotion of self-trapped excitons from the lowest metastable level to the second excited level in KCl.