Crystal-field theory calculations for Fe2+ Ions in bronzite, augite, and olivine
Crystal-field theory calculations for Fe2+ Ions in bronzite, augite, and olivine
复制标题
青铜矿、辉石和橄榄石中 Fe2 离子的晶体场理论计算
DOI：
10.1007/bf00202312
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发表时间：
1992
影响因子：
1.4
通讯作者：
H. Takeda
中科院分区：
文献类型：
--
作者：
T. Hiroi;H. Takeda
将晶体场理论应用于三种硅酸盐中的Fe2+离子，试图用一个参数来确定所有主要的吸收带。根据x射线衍射研究得到的所有实际原子坐标，用傅里叶方法计算了库仑势能场。引入组态相互作用（CI）方法，计算了中心Fe2+离子最低能谱态的微扰电子分裂能。在粉状青铜矿、奥辉石和橄榄石中观察到的所有主要吸收带，通过优化表示d-电子云膨胀或收缩的一个参数，被分配到这些计算能级之间的跃迁。计算结果与前人对铜榴石的赋值基本一致，而对奥辉石的赋值不同，并且有可能在橄榄石的1-μm复合带中存在隐藏的第四波段。
Crystal-field theory was applied to Fe2+ions in three types of silicates in an attempt to assign all the major absorption bands with only one parameter to adjust. Coulomb potential energy field were calculated by Fourier method based on all the actual atomic coordinates refined by X-ray diffraction studies. Perturbedd-electron splitting energies of the central Fe2+ion were calculated by introducing Configuration Interaction (CI) method for the lowest energy spectral states. All the major absorption bands observed in powdered bronzite, augite, and olivine, were assigned to the transitions between those calculated energy levels by optimizing only one parameter that expresses expansion or contraction ofd-electron cloud. The result of the calculations gives almost the same assignments as the other previous works for bronzites, different assignments for augites, and a possibility of the existence of the fourth band hidden in the composite 1-μm band of olivines.