SS and SOO Mechanisms of the EPR Parameters for 4 A2(3d3 ) State Ion in Trigonal Symmetry Crystal Field

A CDM/ EPR program has been developed using Visual Basic 6. 0. The spin-spin（SS）and spin-otherorbit（SOO）interactions omitted in published works have also been included in the Hamiltonian. The CDM/EPR program can study not only the EPR parameters but also the CF energy levels and wavefunctions for 4A2 （3d3）states ions in crystals. Utilizing the CDM/ EPR program，the EPR parameters and fine spectra for Ruby and Emerald have been investigated. The theoretical results are in good agreement with the experimental findings. The contributions to the EPR parameters and fine spectra arising from SS and SOO interactions have been studied. The investigation shows：① The EPR parameters are mainly induced by SO coupling interaction；② The contribution to the zerofield-splitting（ZFS）arising from SS interaction is appreciable and cannot be omitted，whereas the contributions to the ZFS parameter D arising from SOO interaction are smaller；③ The contribution to the Zeeman g-factors and spectra arising from SS and SOO interactions is slight.