掺Cr^(3+)晶体SrLaGaO_4和Cs_2CdCl_4的EPR理论研究

Theoretical Investigations on the Electron Paramagnetic Resonance for Cr^(3+) in SrLaGaO_4 and Cs_2CdCl_4 Crystals

根据晶体场理论,考虑到掺杂过渡金属离子的半径和价态与基质离子的差异,初步建立四角晶场中杂质离子局域结构崎变模型。并采用半自洽场d轨道模型、EPR参量高阶微扰方法、局域结构模型和点电荷模型,在强场图象中解释了掺Cr3+晶体SrLaGaO4和Cs2CdCl4的EPR谱(零场分裂参量D值以及g因子)。理论计算值与实验数据吻合较好,表明过渡金属离子局域结构伸缩模型是合理的,可运用到四角对称的其他晶体谱学特性研究。

On basis of crystal field theory, considered the radius and valence charge of transition metal ion are not the same with that of the substituted one in tetragonal crystal system, the local structure extension model of transition metal ion （3d^n/10-n） has been built. Furthermore, in a tetragonal strong field scheme by semi-SCF d-orbit wave functions model of free ions, high-order perturbation method, point-charge crystal field model and local structure extension model, the EPR parameter of SrLaGaO4 ： Cr^3＋ and Cs2CdCl4： Cr^3＋ have been explained. The calculated results agree well with the experimental findings, which indicated that the extension model used in this paper was reasonable, and it could be fit for other tetragonal crystal system.