YAG∶Cr^(3+)晶体精细光谱结构研究

Researches on Fine Spectra Structure in YAG∶Cr^(3+)Crystal

采用不同的晶体畸变模型,利用CDM(completediagonalizationmethod)方法对YAG∶Cr3+晶体的EPR参量进行了系统研究·通过计算结果对晶格畸变模型进行了分析.结果表明,在三角对称下,对杂质离子电荷与中心离子电荷相等的情况,不适合用杂质离子沿C3轴位移的模型来研究晶体的局域结构,而且由于基态和第一激发态的零场分裂都对局域结构微变非常敏感,因此仅由基态零场分裂来确定晶格局域结构是不可靠的·同时结果表明,Cr3+离子进入YAG晶体后,产生了Δθ=1.88°的三角畸变·从而成功统一地解释了YAG∶Cr3+晶体的EPR参量和精细光谱结构·

The EPR parameters and fine spectra for Cr^3＋ ion in YAG crystal were studied by using two distortion models and complete diagonalization method（CDM）. The investigations consider for the first time the spin-spin （SS） and spin-other-orbit （SOO） interactions. The studies show that the local structure in the YAG ＇ Cr^3＋ crystal is of the compressed trigonal distortion （Δθ= 1. 88°）. Accordingly, the EPR parameters and fine spectra for Cr^3＋ ion in YAG crystal are explained successfully. By analyzing these models, it shows that the impurity ion moving model is not suitable if there are the same charge for the impurity ion and host ion. Since local structure is sensitive to both ground state zero field splitting （ZFS） and the first excited state ZFS, it is not reliable to decide local lattice distortion only using ground state ZFS parameter D.