Es. Gafiatulina et al., CREATION OF EXCITONS AND DEFECTS IN A CSI CRYSTAL DURING PULSED ELECTRON-IRRADIATION, Physics of the solid state, 40(4), 1998, pp. 586-590
Data presented on the influence of the temperature in the range 80-650
K on the spectral kinetics of the luminescence and transient absorpti
on of unactivated CsI crystals under irradiation by pulsed electron be
ams ([E]=0.25 MeV, t(1/2)=15 ns, j=20 A/cm(2)). The structure of the s
hort-wavelength part of the transient absorption spectra at T=80-350 K
exhibits features, suggesting that the nuclear subsystem of self-trap
ped excitons (STE's) transforms repeatedly during their lifetime until
their radiative annihilation at T greater than or equal to 80 K, alte
rnately occupying di-and trihalide ionic configurations. It is establi
shed that a temperature-induced increase in the yield of radiation def
ects, as well as F and H color centers, and quenching of the UV lumine
scence in CsI occur in the same temperature region (above 350 K) and a
re characterized by identical thermal activation energies (similar to
0.22 eV). It is postulated that the STE's in a CsI crystal can have a
trihalide ionic core with either an on-center or off-center configurat
ion; the high-temperature luminescence of CsI crystals is associated w
ith the radiative annihilation of an off-center STE with the structure
(I-(I(0)I(-)e(-))). (C) 1998 American Institute of Physics.