Absorption, circular dichroism and magnetic circular dichroism spectra of Na3Pr(C4H4O5)3· 2NaClO4·6H2O

Abstract

Polarized absorption, circular dichroism, Zeeman effect and magnetic circular dichroism spectroscopy have been used to study single crystals of trigonal trisodium praseodymium tris(oxydiacetate) di(sodium perchlorate) hexahydrate, Na₃Pr(C₄H₄O₅)₃·2NaClO₄·6H₂O. Transitions between the crystal field levels of ³H₄ and ¹D₂, ³P_0,1,2 and ¹I₆ have been observed and assigned. The crystal undergoes an order–disorder phase transition between 300 and 77 K which lowers the lanthanide site symmetry to C₂. The distortion caused by this phase transition is small and a crystal field calculation within the D₃ point group gives a reasonable fit of the experimentally observed energy levels and supports the assignments of the crystal field components. The estimated values of the parameters are F₂= 302, F₄= 64.3, F₆= 5.9, ζ= 723, A₂₀= 150, A₄₀=–1508, A₄₃= 1128, A₆₀= 617, A₆₃= 308 and A₆₆= 368 cm^–1.