Ultraviolet Absorption Spectra of Ce 3+ in Alkaline-Earth Fluorides
Ultraviolet Absorption Spectra of Ce 3+ in Alkaline-Earth Fluorides
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碱土氟化物中Ce 3 的紫外吸收光谱
DOI：
10.1103/physrev.154.270
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发表时间：
1967
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
在室温和液氮温度下测量了碱土氟化物CaF 2、SrF 2和BaF 2晶体中0.005%Ce3+的紫外吸收光谱。所有三种宿主的光谱中的一般特征是相似的。Ce 3+浓度为0.005%~ 5%时，在CaF 2中的紫外吸收光谱显示出三个互构吸收区：（1）4f → 5d吸收带，在31000 ~ 56000 cm-1之间，半宽约2000 cm-1，Ce 3+浓度为10%~ 20%时，4f → 6s吸收带，在60000 ~ 77000 cm-1之间，宽而弱，最大吸收峰在70000 cm-1附近;以及（3）电荷转移吸收，F-（2 p 6）→ Ce 3+（6 s），表现为主体Ca F 2的吸收边在约80 000 cm-1处的明显红移。这三个吸收区域的分配是基于带的位置、宽度、数量、振子强度和温度依赖性。Ce 3+浓度≥ 0.1%时，其紫外吸收光谱的变化是由于Ce 3+-F-间隙原子团簇的形成所致。最低的4 f→ 5 d带的电子振动结构可以用赝定域振动来考虑，就像瓦格纳和布朗处理的碱金属卤化物中的几个二价稀土离子的情况一样。
The ultraviolet absorption spectra of Ce 3+, 0.005%, in crystals of the alkaline-earth fluorides Ca F 2, Sr F 2, and Ba F 2 have been measured at both room and liquid-nitrogen temperatures. The general features in the spectra of all three hosts are similar. The ultraviolet spectra of Ce 3+, 0.005% to 5%, in Ca F 2 show three regions of interconfigurational absorption which may be assigned as:(1) 4 f→ 5 d bands from about 31 000 to 56 000 cm− 1, with half-width about 2000 cm− 1 at Ce 3+ concentration∼ 10− 2%;(2) 4 f→ 6 s weak and broad band from 60 000 to about 77 000 cm− 1 with maximal absorption at about 70 000 cm− 1; and (3) a charge-transfer absorption, F−(2 p 6)→ Ce 3+(6 s), appearing as an apparent red shift of the absorption edge of the host Ca F 2 at approximately 80 000 cm− 1. The assignments of these three regions of absorption are based on the location, width, number, oscillator strength, and temperature dependence of the bands. The effect of large Ce 3+ concentration,≥ 0.1%, on the uv absorption spectra of Ce 3+ is interpreted as the result of cluster formation from pairs of Ce 3+-interstitial F−. The vibronic structure in the lowest 4 f→ 5 d band may be conceived in terms of pseudolocalized vibrations, as in the case of several divalent rare-earth ions in alkali halides treated by Wagner and Bron.