Luminescence of Cs2NaScCl6:Pr3+: Effects of Changing the Elpasolite Lattice Parameter

Abstract

The luminescence spectrum of Cs2NaScCl6:Pr3+ (0.1 at.%) has been recorded at temperatures down to 10 K and assigned between 20,800 and 9900 cm−1. Twenty‐three energy levels of the 4f2 configuration Pr3+ ion were located and then fitted by the conventional 4f2 crystal field calculation, as well as by a configuration interaction assisted crystal field (CIACF) calculation. The latter gave a much better fit. A comparison of the fit for Cs2NaScCl6:Pr3+ with fits upon the same set of energy levels in Cs2NaYCl6:Pr3+ and Cs2NaPrCl6, where the fifth nearest neighbor of Pr3+ is changed and the lattice parameter increases along this series, shows a decrease in the magnitudes of the crystal field parameters, which were also semiquantitatively simulated. Several facets of the emission spectra are interesting, including the observation of weak progressions in the totally symmetric Pr–Cl stretching vibration and the occurrences of the resonance of electronic and vibronic states. The spectra of Cs2NaScCl6:Pr3+ (1 at.%) differ considerably from those of the more dilute system and show that other species are formed rather than a complete substitution of the Sc3+ sites by Pr3+.