Crystal field analysis of Pr 3+ and Nd 3+ ions in KR(WO 4) 2 (R=Y or Gd) potassium rare-earth tungstates

Abstract

Absorption and emission spectra of KY(WO 4) 2:Pr 3+ and KGd(WO 4) 2:Pr 3+ crystals are recorded at 77 K, and the experimental energy level schemes of Pr 3+ ions are determined. Crystal field analysis for Pr 3+ ions is carried out using the true C 2 point symmetry. The initial set of crystal field parameters was obtained from superposition model calculations. Experimental crystal field energies of KY(WO 4) 2:Pr 3+ and KGd(WO 4) 2:Pr 3+ crystals are fitted with the root mean squares deviation σ=16.4 and 17.5 cm −1, respectively. The consistency of these sets of crystal field parameter for Pr 3+ ions is confirmed from comparative crystal field calculations for Nd 3+ ions doped in KY(WO 4) 2 crystal resulting in σ=8.2 cm −1.