从头计算法计算Yb^(3+)掺杂钽酸盐的晶体场参数和能级结构  

Ab-initio calculations of the crystal-field parameters and energy level structure for Yb^(3+) doped in tantalate

作　　者：高进云[1,2] 张庆礼[1] 孙敦陆[1] 刘文鹏[1] 杨华军[1,2] 王小飞[1,2] 殷绍唐[1] 

机构地区：[1]中国科学院安徽光学精密机械研究所安徽省光子器件与材料重点实验室,合肥230031 [2]中国科学院研究生院,北京100049

出　　处：《物理学报》2013年第1期119-125,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:90922003;51172236;50872135;91122021);中国科学院知识创新工程(批准号:YYYJ-1002)资助的课题~~

摘　　要：介绍了一种基于从头计算的DV-Xα方法和有效哈密顿量模型,它可以计算晶体中掺杂离子的晶体场参数和旋轨耦合参数,尤其适合计算低对称性的晶体.对于低对称性的晶体,参数的数目比能级的数目多,因此通过实验能级拟合确定所有的参数不太准确,而从头计算法可以准确地确定所有的晶体场参数和旋轨耦合参数.首先用这种模型计算了Yb3+掺杂GdTaO4晶体中的晶体场参数和旋轨耦合参数,然后给出了Yb3+在GdTaO4中的能级结构,并分析了Yb3+:GdTaO4的发射谱形成一个连续的发射带.这有利于激光的调谐和锁模激光输出,预言了Yb3+:GdTaO4有望成为新型全固态超短脉冲激光工作物质.同样用这种模型分别计算了Yb3+掺杂YTaO4和ScTaO4中的晶体场参数和旋轨耦合参数,并给出了Yb3+在YTaO4和ScTaO4中的能级结构,得到了与Yb3+:GdTaO4晶体类似的结论.In this paper, the DV-Xα method of ab-initio calculations and the effective Hamiltonian model are introduced to calculate the crystal-field and spin-orbit parameters of rare earth ions doped in various crystals, especially for the crystal with low-symmetry. For the low-symmetry crystal, the number of parameters is more than that of energy levels, thus experimental energy levels fitting cannot determine all parameters, while ab-initio calculations can determine all crystal-field and spin-orbit parameters accurately. Firstly, the crystal-field and spin-orbit parameters of Yb^3＋ doped in GdTaO4 crystal are calculated by this model, and then the energy level structure of Yb^3＋ ：GdTaO4 is given and the continuous emission band of Yb3＋ ：GdTaO4 emission spectrum is analyzed, which is conducive to the laser tunable and laser mode-locking output, so Yb3＋：GdTaO4 is a potential laser medium for high efficiency laser operation and new ultrashort pulse output. Also, the crystal-field and spin-orbit parameters of Yb^3＋ doped in YTaO4 and ScTaO4 are calculated by this model, and the energy level structures of Yb^3＋ ：YTaO4 and Yb^3＋ ：ScTaO4 are given, which leads to a conclusion similar to that drawn from the Yb^3＋ ：GdTaO4 crystal.

关 键 词：稀土钽酸盐 DV-Xα方法 有效哈密顿量模型 晶体场参数 

分 类 号：O73[理学—晶体学]