Bi_(4)Ge_(3)O_(12) ∶ Er^(3+)晶体中的高阶混合效应对EPRg因子的影响

High-Order Mixing Effects on EPR g-factors for Er^(3+) Doped Bi_(4)Ge_(3)O_(12) Crystals

通过对角化364×364完全能量矩阵的理论方法,对掺杂在Bi_(4)Ge_(3)O_(12)晶体中的Er^(3+)的Stark能级和EPR参数进行了研究,同时,定量分析了高阶晶体场混合效应和J-J混合效应对EPR g因子的影响。研究结果表明:对Er^(3+)来说,最主要的J-J混合效应来源于多重态谱项2 K 15/2,其对EPR g因子的贡献约占2.5%,而最主要的高阶晶体场混合效应来源于第一激发多重态^(4)I_(13/2)和基态多重态^(4)I_(15/2)之间的晶体场混合,其对各向异性g因子中g⊥的贡献大致是g//的两倍(即g⊥约占0.21%,g//约占0.092%),其他更高阶的晶体场混合和J-J混合效应可以忽略不计。因此,对于Er^(3+)掺杂的络合物系统来说,只考虑基态多重态4 I 15/2对EPR g因子的贡献应该是一个很好的近似。

Stark levels and EPR parameters of Er^(3+)doped in Bi_(4)Ge_(3)O_(12) crystal were studied by diagonalizing 364×364 complete energy matrices.Simultaneously,the crystal-field and J-J mixing effects on the EPR g-factors from the higher lying manifolds were evaluated,quantitatively.The results indicate that the dominant J-J mixing contribution from manifold 2 K 15/2 accounts for about 2.5%for the Er^(3+).However,the most significant high-order mixing effect is from the crystal-field admixture between the first excited manifold ^(4)I_(13/2) and ground manifold 4I 15/2,where the contribution to g⊥is almost twice as much as that to g//(0.21%for g⊥,0.092%for g//).The other crystal-field and J-J mixing effects from the higher lying manifolds can be neglected.Therefore,only considering the contribution of ground manifold ^(4)I_(15/2 )to EPR g-factor is a good approximation for the complex system doped with Er^(3+)ions.