晶体NiX2(X=Cl,Br,I)的光谱和电子顺磁共振谱研究

在强场耦合图像中,采用双自旋-轨道耦合(SO)参量模型建立了过渡族3d2(3d8)离子的三角对称下全组态光谱能级和电子顺磁共振(EPR)公式.与经典的晶体场理论(仅考虑中心金属离子的自旋-轨道耦合作用)相比较,该公式还包括了配体离子的自旋-轨道耦合作用的贡献,这一模型在应用于计算共价性较强的晶体光谱和电子顺磁共振谱可得到合理的结果.作为验证,用完全对角化方法研究了品体NiX2(X=Cl,Br,I)的光谱和电子顺磁共振谱,结果表明,理论与实验很好地符合.建立的全组态谱能级和电子顺磁共振公式为更精确地计算光谱和电子顺磁共振谱提供了一条可行方法.

Investigations of Optical and EPR Spectra for NiX2(X=Cl,Br,I)Crystals

The formulae of optical spectral energy levels and electron paramagnetic resonance (EPR) spectra of all configurations in trigonal symmetry of 3d2(3d8) ions are established on basis of strong field coupling mechanism by using the two-spin-orbit-coupling parameter model. Compared with the classical crystal-field approach which has only taken the spin-orbit coupling of the central transition-metal ions into account, the contribution of the spin-orbit coupling of the ligand ions to the optical and EPR spectra has been included in these formulae. When the optical and EPR spectra of the strong covalent crystals are calculated, reasonable results can be obtained if the two-spin-orbit-coupling parameter model has been put into action. As an application, the optical and EPR spectra of the NiX2(X=Cl,Br,I) crystals have been studied by the complete diagonalization method. The calculated results are in good agreement with experimental findings. From the investigation, a valid method to calculate the optical and EPR spectra of all configurations more accurately is provided.