Direct spectroscopic evidence of 8- and 9-fold coordinated europium(III) species in H(2)O and D(2)O.
In the present paper a detailed analysis of high-resolution luminescence spectra of Eu(III)-H(2)O species in frozen aqueous solution (T = 5 K) is presented. From the total luminescence spectra (TLS, excitation vs emission) and the luminescence decay matrixes (time vs emission), fundamental species-selective spectroscopic parameters are determined: excitation wavelength λ(exc), decay time τ, crystal field energy splitting ΔE (crystal field strength parameter N(ν)(B(2q))), crystal field parameters B(20) and B(22), asymmetry ratio r, and point symmetry group. The spectroscopic findings clearly show the presence of two distinct Eu(III) aquo species. Samples prepared with different counterions (Cl(-), ClO(4)(-)) and at different pH values (2 and 5) yielded comparable results. Furthermore, in D(2)O solutions the same two species were found, with similar spectral properties but much longer decay times. On the basis of the spectroscopic analysis, the two species were attributed to 8- and 9-fold coordinated Eu(III) aquo ions.
Institute of Chemistry (Physical Chemistry), University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
Bettina
B
Marmodée
Karolina
K
Jahn
Freek
F
Ariese
Cees
C
Gooijer
Michael U
MU
Kumke
D002712:Chlorides / Q000737:chemistry; D017666:Deuterium Oxide / Q000737:chemistry*; D005063:Europium / Q000737:chemistry*; D008163:Luminescent Measurements; D010472:Perchlorates / Q000737:chemistry; D013057:Spectrum Analysis; D013696:Temperature
D002712:Chlorides; D010472:Perchlorates; D005063:Europium; D017666:Deuterium Oxide; C494474:perchlorate