Dynamic studies on the time-resolved fluorescence of Sm2+ in BaCl2

The time dependence of Sm2+ fluorescence in orthorhombic BaCl2 was investigated between 77 and 300 K. The thermal quenching mechanism of the 4f–4f emissions of Sm2+ was examined. The position of the lowest level of Sm2+ 4f55d states was calculated from the temperature dependence of 5D1 lifetime by the two-step quenching model and was estimated in good approximation from the emission and excitation peaks by the electron–phonon coupling theory. A growing process of 5D0–7F0 emission and a double-decay process of 5d–4f emission were observed in the time-resolved fluorescence. They show clearly the population transfer among the Sm2+ excited states via thermal transition.