Exploration of structural, vibrational and spectroscopic properties of self-activated orthorhombic double molybdate RbEu(MoO 4 ) 2 with isolated MoO 4 units

Abstract

RbEu(MoO 4 ) 2 is synthesized by the two-step solid state reaction method. The crystal structure of RbEu(MoO 4 ) 2 is defined by Rietveld analysis in space group Pbcn with cell parameters a = 5.13502(5), b = 18.8581(2) and c = 8.12849(7) Å, V = 787.13(1) Å 3 , Z = 4 (R B = 0.86%). This molybdate possesses its phase transition at 817 K and melts at 1250 K. The Raman spectra were measured with the excitation at λ = 1064 and 514.5 nm. The photoluminescence spectrum is evaluated under the excitation at 514.5 nm. The absolute domination of hypersensitive 5 D 0 → 7 F 2 transition is observed. The ultranarrow 5 D 0 → 7 F 0 transition in RbEu(MoO 4 ) 2 is positioned at 580.2 nm being 0.2 nm blue shifted, with respect to that in Eu 2 (MoO 4 ) 3