The exciton luminescence of undoped and doped crystals of various origins and with various dopant contents was studied at 4.2 to 300K under excitation by photons with energies of up to 6.2eV. The effect of uniaxial stressing, along the <100> axis at 4.2K, upon the luminescence of self-trapped excitons and various types of localized exciton was examined. Some of the emission bands were attributed to various relatively large lattice imperfections. Bands which peaked at 4.32, 4.25 and 4.03eV were found to arise from on-center configurations of localized excitons and were assumed to be connected with compressed and expanded crystal lattice regions and with some larger lattice distortions or vacancy aggregates, respectively. Peculiarities of the exciton luminescence characteristics, their stress-induced changes and the classification of excitons with respect to lattice relaxation were described.

Effect of Uniaxial Stress on Exciton Luminescence in CsI Crystals. V.Babin, A.Elango, K.Kalder, S.Zazubovich: Physica Status Solidi B, 1999, 212[1], 185-98