THEORY OF PHOTOCHROMIC CENTERS IN CAF2
THEORY OF PHOTOCHROMIC CENTERS IN CAF2
复制标题
DOI：
10.1103/physrevb.3.536
复制
发表时间：
1971-01-01
期刊：
影响因子：
--
通讯作者：
ALIG, RC
中科院分区：
文献类型：
--
作者：
ALIG, RC
根据最近的光学和EPR工作，提出了CaF2中电离的和热稳定的光致变色中心是由一个和两个电子结合在一个靠近三价杂质的阴离子空位上。对于电离中心，我们证明了杂质离子的引入对孤立F中心的能级和波函数没有强烈的扰动作用。由于形成这些中心的Y、La、Ce、Gd、Tb和Lu等杂质的二价离子具有与F中心波函数重叠的低位S和d价轨道，我们研究了F电子轨道和这些杂质轨道的线性组合可能形成的缺陷-杂质轨道。基于这种缺陷-杂质轨道描述的预测与稳定和电离光致变色中心的光学和EPR数据是一致的。
On the basis of recent optical and EPR work, it has been suggested that the ionized and thermally stable photochromic centers in Ca F 2 consist of one and two electrons bound at an anion vacancy adjacent to a trivalent impurity cation. For the ionized center, we have shown that the energy levels and wave functions of the isolated F center are not strongly perturbed by the introduction of the impurity ion. Since the divalent ions of the impurities which are found to form these centers, ie, Y, La, Ce, Gd, Tb, and Lu, have low-lying s and d valence orbitals which overlap the F-center wave functions, we have investigated the defect-impurity orbitals which may be formed from a linear combination of F electron orbitals and these impurity orbitals. The predictions based on this defect-impurity orbital description are found to be consistent with the optical and EPR data for the stable and ionized photochromic centers.