测试了Nd3+:GGG单晶在可见和近红外波段的吸收光谱，并分析指认了它的实验能级，通过从头计算的DV-Xα方法计算得到了它的晶体场参数和旋轨耦合参数。 用Nd3+:GGG在77 K和300 K的156个、88个实验能级，拟合了它的自由离子参数和晶体场参数，均方根误差(即拟合精度)σ分别为15.79 cm-1和 11.48 cm-1。结果表明晶体场参数的拟合结果和从头计算值符合的很好。最后比较了拟合得到的Nd3+:GGG和已报道Nd3+:YAG 的自由离子参数和晶体场参数。

The absorption spectrum of Nd3+ions doped into Gd3 Ga5 O12 (GGG) single crystal was analyzed in the visible and near infrared region. Its crystal-field and spin-orbit parameters were calculated with the DV-Xα method, which belongs to an abinitio calculation. Meanwhile, its free-ions and crystal-field parameters were also been fitted to the experimental energy levels in 300 K and 77 K with the root mean square deviation of 15.79 cm-1 and 11.48 cm-1, respectively. According to the crystal-field calculations, 156 levels of Nd3+ions in 77 K and 88 levels of Nd3+ions in 300 K were assigned. The results indicated that the fitted and calculated crystal-field parameters by DV-Xα are consistent very well. Finally, the fitting results of free-ions and crystal-field parameters are compared with those already reported for Nd3+:YAG.