Tanner Peter A, Mak Chris S K, Edelstein Norman M, Murdoch Keith M, Liu Guokiu, Huang Jin, Seijo Luis, Barandiarán Zoila
Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, Peoples' Republic of China.
J Am Chem Soc. 2003 Oct 29;125(43):13225-33. doi: 10.1021/ja036659x.
The experimental determination of the electronic energy levels for Ce(3+) in some chloroelpasolite hosts for both the ground 4f(1) and the excited 5d(1) configurations is described. High-resolution f-f absorption and f-(2)T(2g) d absorption and emission spectra have been recorded at low temperatures for Ce(3+) diluted into various hexachloroelpasolite lattices. A fluorescence spectrum at approximately 50 000 cm(-1) is tentatively assigned to the emission from the highest 5d crystal field level, (2)E(g), of a Ce(3+) impurity in Cs(2)NaErCl(6), enabling the values of all the energy levels of both the 4f(1) and 5d(1) configurations to be given for Ce(3+) in elpasolite hosts. Vibronic structure superimposed on the electronic transitions is analyzed in terms of a simple configurational coordinate model involving the ground and excited configurations. It is found that the difference in the Ce-Cl bond length between the 4f(1) and 5d(1) configurations is approximately 0.04 A. Ab initio model potential calculations on the (CeCl(6))(3-) cluster embedded in a reliable representation of the Cs(2)NaYCl(6) host support these conclusions.
本文描述了在一些氯铯榴石基质中，对Ce(3+)的基态4f(1)和激发态5d(1)构型的电子能级进行的实验测定。对于稀释在各种六氯铯榴石晶格中的Ce(3+)，在低温下记录了高分辨率的f-f吸收、f-(2)T(2g) d吸收和发射光谱。在Cs(2)NaErCl(6)中，Ce(3+)杂质的最高5d晶体场能级(2)E(g)的发射初步确定了约50000 cm(-1)处的荧光光谱，从而能够给出铯榴石基质中Ce(3+)的4f(1)和5d(1)构型所有能级的值。根据涉及基态和激发态构型的简单构型坐标模型，分析了叠加在电子跃迁上的振动结构。结果发现，4f(1)和5d(1)构型之间Ce-Cl键长的差异约为0.04 Å。嵌入Cs(2)NaYCl(6)基质可靠表示中的(CeCl(6))(3-)团簇的从头算模型势计算支持了这些结论。
