Optical absorption spectra of Pr3+ in maleato complexes

Abstract

It is shown that the absorption spectra of Pr3+(4f2) can be conveniently analysed in terms of Racah parameters (E1, E2, E3), spin-orbit coupling constant(ζ) and configuration-interaction parameters (α, β, γ) by incorporating relationships based on the matrix elements corresponding to the 3P1, 3P0, 3F3 and 3H5 terms and experimental transition energies. The proposed method leads to more reliable results than those from the usual Taylor series method. The absorption spectra of Pr(Hmale)3·7H2O (H2male = maleic acid) and Pr3+-doped maleato complexes of Zn2+, Mg2+ and Cd2+ have been analysed for the energy parameters. The parameters E1, E3 and ζ were invariably found to be significantly less than the free-ion values, while E2 remains practically unchanged. These variations are accounted for in terms of weak covalency and the nephelauxetic effect. The spectral intensities have been analysed in terms of the Judd–Ofelt parameters and predicted lifetimes have been calculated for the transitions 3P2â†�3H4, 3P1â†�3H4, 3P0â†�3H4 and 1D2â†�3H4.