Optical absorption spectra, crystal-field analysis, and electric dipole intensity parameters for europium in Na 3[En(ODA) 3]-2NaClO 4·6H 2O

Abstract

Locations and assignments of 61 crystal-field levels are reported for Eu 3+ in the trigonal Na 3[Eu(oxydiacetate) 3]· 2NaClO 46H 2O system. These energy levels span the 0-37400 cm − energy region, and they were located and assigned from optical emission spectra and from axial and orthoaxial (σ and π-polarized) absorption measurements on single crystals. The assigned crystal-field levels span 22 different multiplet manifolds, with principal parentages derived from seven different f 6 Russell-Saunders terms ( 2F, 5D, 5L, 5H, 5F, 5I, and 5K). The assigned levels are analyzed in terms of a 26-parameter electronic Hamiltonian in which six of the parameters are defined to represent the 4f-electron/crystal-field interactions for Eu 3+ ions located at sites with trigonal dihedral (D 3) symmetry. Quantitative line intensities are reported for 39 individual 4f→4f (crystal-field) transitions observed in the low-temperature (10 K) absorption spectra, and these intensity data are analyzed in terms of a general parametric model for 4f→4f transition intensities in lanthanide systems. The energy and intensity parameterizations provide a basis for calculating the 4f→4f absorption spectra of Eu 3+ in Na 3[Eu(oxydiacetate) 3]· 2NaClO 4·6H 2O over a wide spectral range and excellent agreement between calculated and experimentally measured spectra is obtained. Several of the intensity parameters determined to be important in this study carry information of particular significance to understanding the structural and mechanisticbases of lanthanid