Ultraviolet-Absorption Spectra of Europium and Ytterbium in Alkaline Earth Fluorides
Ultraviolet-Absorption Spectra of Europium and Ytterbium in Alkaline Earth Fluorides
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DOI：
10.1103/physrev.184.348
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发表时间：
1969-08
期刊：
影响因子：
--
通讯作者：
E. Loh
中科院分区：
文献类型：
--
作者：
E. Loh
Ca F 2 晶体中铕和镱离子的紫外吸收光谱已在室温和液氮温度下测量。它们的光谱在吸收带的一般位置上彼此相似。两个光谱均由以下部分组成：(i) 4 f→ 5 d 能带，在约 24 000 cm− 1 和约 50 000 cm− 1 之间，由于孤立的 RE 2+，晶体场强～ 17 000 cm− 1 在 e g 和 t 2 g 能带之间；(ii) 4 f→ 5 d 能带，由于 RE 2+ 的原因，移动～ 9 000 cm− 1 到更高的能量被 R E 3+ 邻居包围的离子；(iii) a 4 f→ 6 p Ca F 2 中Eu 2+ 的宽弱能带，最大位于∼ 71 000 cm− 1； (iv) 由于孤立的 RE 3+ 和簇离子 RE 3+，4 f→ 5 d 谱带高于~ 64 000 cm− 1。孤立的 RE 2+(4 f n) 和 RE 3+(4 f n) 离子的吸收光谱中的结构可以解释为通过具有例如或 t 2 g 晶体场对称性的 5 d 电子与 4 f n- 1 核的接地多重态中的电子之间的相互作用而形成。
The ultraviolet-absorption spectra of europium and ytterbium ions in Ca F 2 crystals have been measured at room and liquid-nitrogen temperatures. Their spectra are similar to each other in the general location of their absorption bands. Both spectra consist of:(i) 4 f→ 5 d bands, between about 24 000 cm− 1 and about 50 000 cm− 1, due to isolated R E 2+ with crystal field strength∼ 17 000 cm− 1 between e g and t 2 g bands;(ii) 4 f→ 5 d bands, shifted∼ 9 000 cm− 1 to higher energy, due to R E 2+ ions surrounded by R E 3+ neighbors;(iii) a 4 f→ 6 p broad and weak band of Eu 2+ in Ca F 2 with maximum at∼ 71 000 cm− 1; and (iv) 4 f→ 5 d bands above∼ 64 000 cm− 1 due to isolated R E 3+ and cluster-ion R E 3+. The structure in the absorption spectra of both isolated RE 2+(4 f n) and RE 3+(4 f n) ions can be interpreted as formed through interaction between a 5 d electron having e g or t 2 g crystal field symmetry and electrons in the ground multiplet of the 4 f n− 1 core.