Dynamic studies on the time-resolved fluorescence of Sm 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.