d^4(D_(2d))络离子的EPR理论与ZnS:Cr^(2+)的光—磁性质研究

An EPR Theory for d^4(D_(2d))Ions and a Study of the Optical and Magnetic Properties of ZnS:Cr^(2+)

本文通过对ZnS:Cr^(2+)晶体光学吸收谱及EPR谱的观测资料的分析,发现Cr^(2+)杂质的有效晶场并非常所认为的四硫配位四面体结构。采用O_h点群表象方块准对角型简化强场方案,首次建立了d^4(D_(2d)~*)全组态混合EPR理论。用这一理论对Zns:Cr^(2+)的自旋允许谱精细结构、基态零场分裂、g因子、Zeeman能级以及EPR条件等进行了统一的计算。理论结果与实验资料高度一致。结果表明,ZnS:Cr^(2+)中Cr^(2+)离子的有效晶场应为六硫配位D_(2d)畸变八面体结构。

Analyses were given to the optical and EPR spectrum of ZnS:Cr^(2+). An unified calculation was given to the fine structure of the spin-allowed bands, the ground state zero-field splitting, the Zeeman splitting and the EPR g factors, by the complete configuration mixing EPR theory for d(D_(2d)) systems. The results showed that the effective crystal field surrounding the Cr^(2+) ions is of octahedral rather than tetrahedral symmetry as reported by all previous works.