Luminescence, Trapping, and F Centers in Lithium Fluoride Crystals

Single crystals of lithium fluoride from various sources were investigated by optical absorption in the visible and in the vacuum ultraviolet, irradiation with x rays or with ultraviolet from a microwave discharge source, measurement of total luminescence output and of luminescence emission spectra as a function of temperature, optical and thermal bleaching of absorption centers, and thermally stimulated luminescence. In addition to obtaining specific quantitative data on the parameters of the F center, hole traps and luminescence centers in lithium fluoride, it is concluded that the dominant luminescence and trapping centers are associated with specific impurities in the lithium fluoride, and that the F centers are not involved in the production of visible x-ray-induced or thermally stimulated luminescence.