Electronic energy-level structure of 4f6 configuration in europium(III) triacetate tetrahydrate

Analysis of high-resolution absorption and emission spectra of europium(III) triacetate tetrahydrate (EuAC) crystal enabled assignment of 130 experimental crystal-field levels of the 4f6 configuration between 0 and 35,050 cm−1. These experimentally determined levels were simulated using a semi-empirical 35 parameters Hamiltonian representing the combined free-ion and crystal-field interactions for Eu3+ ion in the C1 symmetry site, with the final relatively low r.m.s. deviation of 9.0 cm−1. The reliable starting values of Bqk parameters were obtained from the superposition model analysis. The crystal-field strength (Scf) for EuAC is slightly smaller than for europium(III) trioxydiacetate complex (EuODA). It is probably brought about by the presence of two water molecules in the first coordination sphere of the metal ion in the acetate crystal.