The role of radiolysis products in in situ luminescence of Li2O

A new phenomenon of an "excess luminescence" (EL) in Li2O observed at 4.5-2.5 eV under light ion (H+, He+) irradiation during the rise of temperature (>573 K) was studied. The essence of the EL is in the rapid pulsed increase of the luminescence intensity. It is proposed that this phenomenon is based on the thermo-dissociation of colloidal Li into Li lattice ions, F+ and F-O centers, and oxygen vacancies. Formed oxygen vacancies capture electrons during the irradiation and form excited F-centers, whose relaxation gives the EL. This phenomenon was reproduced using X-ray irradiation and a sample containing colloidal Li introduced by irradiation with electron accelerator to an absorbed dose of 105 MGy. (C) 1998 Elsevier Science B.V.