Spectral parameters viz. oscillator strengths (P), Judd-Ofelt parameters (τλ), inter-electronic repulsion (Racah)∂Ek parameters (IERP) and nephelauxetic ratio (δE3/δE1) have been determined using aqueous solutions of representative lanthanide (rare earth) (III) ions, Pr(III), Nd(III), Sm(III), Eu(III), and Er(III) and rare earth-doped concentrated (∼ 1.0 M) solutions of pseudogarnets sodiumm-silicate, sodium molybdate and sodiumm-vanadate. These parameters have been studied as a function of (i) symmetry around the Ln(III) ions, and (ii) matrix environment due to different pseudogarnets.
The electronic transitions for various Ln(III) ions and changes in their positions due to corresponding changes in matrix environment are observed to show red shift. The oscillator strength values increase significantly in the sequence aqua <MoO42−<VO3−<SiO32−. The τλ values are found to lie in the orderτ6>τ4>τ2. The∂Ek and∂E3/∂E1 values are observed to lie in the theoretically calculated ranges. The nature of dopant-matrix interaction appears to change from ionic to ionocovalent on going across the Ln(III) series.
Volume 134, 2022
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