Institute of Chemistry (Physical Chemistry), University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
J Phys Chem A. 2010 Dec 23;114(50):13050-4. doi: 10.1021/jp1094036. Epub 2010 Dec 1.
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.
本文详细分析了在冷冻水溶液（T = 5 K）中 Eu(III)-H(2)O 物种的高分辨率发光光谱。从总发光光谱（TLS，激发与发射）和发光衰减矩阵（时间与发射）中，确定了基本的物种选择性光谱参数：激发波长 λ(exc)、衰减时间 τ、晶体场能量分裂 ΔE（晶体场强度参数 N(ν)(B(2q)))、晶体场参数 B(20)和 B(22)、不对称比 r 和点对称群。光谱研究结果清楚地表明存在两种不同的 Eu(III)水合物种。使用不同的抗衡离子（Cl(-)、ClO(4)(-))和不同的 pH 值（2 和 5）制备的样品得到了类似的结果。此外，在 D(2)O 溶液中也发现了这两种相同的物种，它们具有相似的光谱特性，但衰减时间要长得多。基于光谱分析，将这两种物质归因于 8 配位和 9 配位的 Eu(III)水合离子。
