LUMINESCENCE AND CRYSTAL-FIELD PARAMETERS OF THE NA-3[EU(DPA)(3)]CENTER-DOT-12H(2)O COMPLEX IN A SINGLE-CRYSTALLINE STATE

Single crystals of Na-3[Eu(DPA)(3)]. 12H(2)O (DPA=dipicolinato) were g rown by the temperature lowering method. Luminescence and excitation s pectra of the crystals are reported. Detailed line assignments for the D-5(0)-->F-7(j) (J=0, 1, 2, 3 and 4) transitions are carried out with the simulation of the luminescence lines in the frame of the free-ion and the crystal-field Hamiltonians. Although the systematic analysis on the baricenter shifting of each excited J states due to the complex ation is need for the emission process, the set of the refined crystal field parameters under the D-2 site symmetry satisfactorily reproduce s the fine splitting of the emission lines. It proves the fact that th e characteristic line splittings are strongly correlated with the site symmetry of Eu(III). (C) 1998 Elsevier Science S.A.