Irradiation defects in Li2O

The behavior of irradiation defects in Li2O was studied by in-situ luminescence measurement method under γ-ray irradiation. The investigation was performed using a single crystal of Li2O in the temperature range 77-298 K. The luminescence emission was observed at wavelength 200-500 nm. Luminescence spectrum at 298 K was found to be consisted of five emission bands at 255 nm (4.86 eV), 300 nm (4.13 eV), 335 nm (3.70 eV), 380 nm (3.26 eV) and 430 nm (2.88 eV). The decay of self-trapped excitons is a result of σ- and π-luminescence at 4.86 and 4.13 eV, respectively. The luminescence emissions at 3.70, 3.26 and 2.88 eV were assigned to the F0, F+ and F2 centers, respectively. The luminescence of 380 nm was treated to be intrinsic, depending on annealing condition of the sample before irradiation. It is considered excitonic mechanism of the luminescence emission. (author)