Characterization of electronic transition energies and trigonal distortion of the (FeO6)9- coordination complex in the Al2O3:Fe3+ system: a simple method for transition-metal ions in a trigonal ligand field.
Characterization of electronic transition energies and trigonal distortion of the (FeO6)9- coordination complex in the Al2O3:Fe3+ system: a simple method for transition-metal ions in a trigonal ligand field.
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DOI：
10.1021/jp062724o
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
K. Xiao-yu;Lu Cheng
中科院分区：
文献类型：
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作者：
K. Xiao-yu;Lu Cheng
基于三角配体场中d5构型离子的电子-电子排斥、配体场和自旋轨道耦合的完整能量矩阵，提出了一种研究电子与分子结构相互关系的理论方法。作为应用，研究了Al2O3:Fe3+体系中Fe3+离子零场分裂的局部畸变结构和温度依赖关系。结果表明：Al2O3:Fe3+体系中（FeO6）（9-）八面体的局部晶格结构存在拉长畸变，畸变值与温度有关。这种拉长的畸变可能是由于Fe3+离子的离子半径明显大于Al3+离子，并且Fe3+离子会沿3倍轴分别推动两个氧三角形向上和向下。通过对角化完整的能量矩阵，我们发现Al2O3:Fe3+体系中Fe3+离子的电子跃迁能和EPR谱的理论结果与实验结果吻合较好。此外，为了了解Al2O3的详细物理和化学性质，首先报道了零场分裂参数和相应畸变参数在50 K <或= T <或= 250 K范围内的理论值。
A theoretical method for studying the inter-relationships between electronic and molecular structure has been proposed on the basis of the complete energy matrices of electron-electron repulsion, the ligand field, and the spin-orbit coupling for the d5 configuration ion in a trigonal ligand field. As an application, the local distortion structure and temperature dependence of zero-field splitting for Fe3+ ions in the Al2O3:Fe3+ system have been investigated. Our results indicate that the local lattice structure of the (FeO6)(9-) octahedron in the Al2O3:Fe3+ system has an elongated distortion and the value of distortion is associated with the temperature. The elongated distortion may be attributed to the facts that the Fe3+ ion has an obviously larger ionic radius than the Al3+ ion and the Fe3+ ion will push the two oxygen triangles upward and downward, respectively, along the 3-fold axis. By diagonalizing the complete energy matrices, we found that the theoretical results of electronic transition energies and EPR spectra for Fe3+ ions in the Al2O3:Fe3+ system are in good agreement with the experimental findings. Moreover, to understand the detailed physical and chemical properties of the Al2O3, the theoretical values of the zero-field splitting parameters and the corresponding distortion parameters in the range 50 K <or= T <or= 250 K are reported first.