Emission spectroscopy and ionic interaction in K5PrLi2F10

Emission spectroscopy of Pr³⁺ in a newly discovered compound, K₅PrLi₂F₁₀, is presented. An energy level diagram of Pr³⁺ in this lattice is given. Dilution with Gd and La shows that concentration quenching caused by Pr-Pr interaction takes place. Dilution with Ce shows, in addition, a strong Pr-Ce interaction resulting in non-radiative ³P₀-¹D₂ conversion occurring in competition with direct ³P₀ to ground state decay. Analysis based on a statistical model is not able to distinguish between Pr interaction with Ce singles or pairs, but it leads to different conclusions than reached for Pr : LaF₃.