ABSORPTION AND LUMIESCENCE SPECTRA OF EU(III) COMPLEXES WITH OXYDIACETATE AND DIPICOLINATE IN AQUEOUS-SOLUTION

Absorption and luminescence spectra of Eu3+ (aquo) and the two differe nt 1:3 Eu3+:ligand systems in aqueous solutions are measured under mil d acidic pH condition. The oxydiacetate (ODA) and dipicolinate (DPA) l igands, forming the similar geometric complexes, are used in this work . The three intensity parameters, Omega(lambda) (lambda=2, 4, and 6) a re empirically determined by applying the Judd-Ofelt theorem to the os cillator strengths of the six absorption bands arising from the ground F-7(0) state. Among the three intensity parameters, the Omega(2) is f ound to response markedly to a miner change in the ligand environment via the F-7(0)-->D-5(0) transition. In addition, the relative oscillat or strengths of the four luminescence bands in the visible region, ass igned to the D-5(0)-->F-7(J) (J=1, 2, 3 and 4) transitions are obtaine d to investigate their sensitivity to the ligand environment. Among th e four bands, the 610 nm band, attributed to the D-5(0)-->F-7(2) trans ition, shows hypersensitivity in the luminescence.