Optical absorption study of irradiation damage in γ-LiA102

Using optical absorption measurements, we studied the defect creation in lithium aluminate single crystals irradiated with 2 MeV α-particles at room temperature and 77 K and with 2.5 MeV electrons at 20 K. The optical absorption spectra of the irradiated samples exhibit four bands in the ultraviolet range. By analogy with other oxides such as MgO, the most intense band (at 5.25 eV) may be assigned to F+-centres. In this hypothesis we propose a configuration of F+-centres coherent with our previous EPR observations