Heteronuclear Eu:Cu trichloroacetate and its polynuclear Eu analogue; their spectroscopy and magnetism
Heteronuclear Eu:Cu trichloroacetate and its polynuclear Eu analogue; their spectroscopy and magnetism
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异核Eu:三氯乙酸铜及其多核Eu类似物；
DOI：
10.1016/s0925-8388(99)00765-3
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发表时间：
2000
影响因子：
6.2
通讯作者：
M. Borzechowska
中科院分区：
文献类型：
--
作者：
J. Legendziewicz;M. Borzechowska
合成了Eu（CCl_3COO）_3·2H_2O（1）和CuEu_2（CCl_3COO）_8·6H_2O（2）的三氯乙酸铕单晶。它们与各自的Er和（Nd：Cu）化合物同构。在1.7-300 K范围内进行了吸收，激发，发射以及磁化率测量。分析了光谱和磁性数据。比较了化合物1和2在室温和低温下的吸收光谱，并将能级分裂的差异描述为CF效应和d-电子离子效应的结果。在293和77 K时，Eu ~（3+）在异质结单晶（2）中的发光被完全猝灭。计算了f-f跃迁的振子强度，分析了辐射过程。在低温激发和发射光谱中记录的弱电子振动成分被本地化的M-L和内部配体模式促进。分析了两个体系（1和2）中L′S′J′能级的斯塔克分量数，确定了金属中心的对称性，并与X射线分析结果进行了比较。第一激发态7 F1的分裂值被用来解释所研究的系统的LT和HT磁性。的杂原子的作用被认为是和相关的数据较早报道的各自的系统。
Single crystals of europium trichloroacetates of formulae Eu(CCl3COO)3·2H2O (1) and CuEu2(CCl3COO)8·6H2O (2) were obtained. They are isomorphic with the respective Er and (Nd:Cu) compounds. Absorption, excitation, emission as well as magnetic susceptibility measurements in the 1.7–300 K range were carried out. The spectroscopic and magnetic data were analysed. The absorption spectra of compounds 1 and 2 at room and low temperature were compared and the differences in the splitting of the levels described as a result of the CF effect and the effect of the d-electron ion. The emission of Eu3+was completely quenched in the heteronuclear single crystal (2) at 293 and 77 K. The oscillator strengths of the f–f transitions were calculated and the radiative processes analysed. Weak vibronic components recorded in the low-temperature excitation and emission spectra were promoted by localised M–L and internal ligand modes. The number of Stark components of the L′S′J′ levels in both systems (1 and 2) was analysed and the symmetries of the metal centres determined and compared with the results of X-ray analysis. The value of the splitting of the first excited state,7F1, was used to explain the LT and HT magnetic properties of the systems under investigation. The role of the heteroatom was considered and related to the data of earlier reported respective systems.