Abstract Polyoxopalladates hosting 3d, 4d or 4f central ions form a new class of molecular materials with well-defined, tunable morphology and ions coordination to be considered as model systems for basic research. We investigated the isotropic X-ray absorption near-edge structure (XANES), X-ray magnetic circular dichroism (XMCD), and X-ray magnetic linear dichroism (XMLD) to monitor the influence of symmetry changes on electronic and magnetic properties. After a brief introductory review about recent results on 3d and 4d transition metal ions, we (i) show that a change of the coordination symmetry from cubic eightfold (tetrahedral) to sixfold (octahedral) reduces the magnetic moment of Co2+ significantly and (ii) investigate whether axial distortions can modify the 4f states of trivalent lanthanide ions. While for Gd3+ there is no effect visible within experimental uncertainties, changes were observed for Dy3+ and Ho3+. The results are compared to atomic multiplet calculations including the intra-atomic spin-dipole term 〈 T z 〉 . Furthermore, several experimental pitfalls are discussed that may lead to misinterpretation of X-ray absorption data but can be excluded in the present study.

中文翻译：

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用软 X 射线磁二色性检测聚氧化钯中 3d、4d 和 4f 中心离子的局部环境变化

摘要 含有 3d、4d 或 4f 中心离子的多氧化钯形成了一类新的分子材料，具有明确的、可调谐的形态和离子配位，被认为是基础研究的模型系统。我们研究了各向同性 X 射线吸收近边结构 (XANES)、X 射线磁性圆二色性 (XMCD) 和 X 射线磁性线性二色性 (XMLD)，以监测对称性变化对电子和磁性的影响。在对 3d 和 4d 过渡金属离子的最新结果进行简要介绍后，我们（i）表明配位对称性从立方八倍（四面体）到六倍（八面体）的变化显着降低了 Co2+ 的磁矩和（ii）研究轴向扭曲是否可以改变三价镧系元素离子的 4f 状态。虽然对于 Gd3+ 在实验不确定性内没有可见的影响，但观察到 Dy3+ 和 Ho3+ 的变化。将结果与包括原子内自旋偶极子项 < T z > 的原子多重态计算进行比较。此外，还讨论了可能导致对 X 射线吸收数据的误解但可以在本研究中排除的几个实验陷阱。