摘要
对(声子边带)可调谐激光晶体金绿宝石(BeAl_2O_4:Cr^(3+))中Cr^(3+)的(3d^3)组态,在O_hC_(3v)C_s逐级近似对称下,用两晶场参量拟合方法得到了全部50个能级的晶场分裂链和相应的波函数,可用于讨论静态奇宇称晶场微扰及电子—声子耦合诱导的d-d跃迁谱强等问题。
For the Cr^(3+) ion being at the site of C_s symmetry in crystal BeAl_2O_4, We have determined its approximate crystal field with symmetry of Ohand C_(3v) group, respechvely. Using two crys- tal-field parameter fitting method we have calculated the energy levels and the wave functions of Cr^(3+) ion (in BeAl_2O_4) in three different symmetric crystal field, and obtain the energy level aplitting chain corresponding to the crystal field group chain O_hC_(3v) C_3. The results can be used to discuss the problems such as d-d transition intensities due to static low-symmetry crys- tal-field and electron-phonon interactions. We found that the stop from O_h to C_(3v) Symmetry in the chain is relatively small but the step from C_(3v) to C_3 is very important. So in the calculation of d-d transition intensitics due to static low-symmetry crystal field, we must treat C_s-symmetry crystal field, and when we calcu- late optical intenaities caused by electron-phonon interaction, only O_h symmetry is enough.
