Luminescence of K5Li2CeF10 and K5Li2LaF10:Ce3+

The positions of 4f–5d levels of cerium in K5Li2LaF10 crystals were determined to be situated at: 33 145 cm−1 (zero phonon line), 43 700, 45 900, 47 250 and 54 500 cm−1. Thermoluminescence glow curves, depend on concentration of Ce3+ and reveals occurrence of several traps with depths ranging from 0.3–0.84 eV; the low value of ratio TL/(TL+ssRL) for K5Li2CeF10 (0.07) suggests that the trapping process is almost negligible in contrast to the K5Li2La0.99Ce0.03F10 (0.44) one, where nearly half of the excitation energy is stored in traps.