Luminescence of Pr³⁺ in minerals

Time-resolved luminescence spectroscopy coupled with selective excitation allows one to identify and assign the emission transitions of Pr³⁺ in natural apatite, scheelite and anhydrite. Under steady state conditions they are hidden by the stronger bands and lines of Eu²⁺, (WO₄)^2-, (MoO₄)^2-, Sm³⁺ and Dy³⁺. Of special interest are the transitions from the ¹S₀ level emitting in the UV part of the spectrum. These transitions make Pr³⁺ doped oxyapatite and anhydrite potential materials for UV laser. The long-lived luminescence of Pr³⁺ in the visible range in apatite in the presence of uranyl and in scheelite may be ascribed to the participation of the ¹S₀ level which serves as a trap of the excitation.