Butorin Sergei M
Condensed Matter Physics of Energy Materials, X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-75120 Uppsala, Sweden.
J Chem Phys. 2021 Oct 28;155(16):164103. doi: 10.1063/5.0062927.
The application of core-to-core (3d-to-4f) resonant inelastic x-ray scattering (RIXS) and high-energy-resolution fluorescence-detected x-ray absorption (HERFD-XAS) at actinide M edges, as techniques with the enhanced sensitivity to changes in the chemical state, was analyzed for trivalent actinide compounds. As an example, a series of actinide chlorides AnCl (An = U, Np, Pu, Am, Cm, Bk, and Cf) was used. The crystal-field multiplet formalism was applied to calculate the 3d-4f RIXS maps, and the HERFD-XAS spectra were extracted as cuts of these RIXS maps along the incident energy axis at the constant emitted energy, corresponding to the maximum of the RIXS intensity. A relation between HERFD and conventional XAS methods was also examined. Despite some differences between profiles of the An M HERFD and conventional XAS spectra of trivalent actinides, the results of calculations indicate that the HERFD method can be used at the An M edge for monitoring even small variations in the An chemical state. As a whole, better agreement between the HERFD and XAS spectra was found for the An M edges as compared to the An M edges. By using the point charge electrostatic model, the dependence of the An M HERFD-XAS spectra on the An coordination number was studied, which indicates the significant sensitivity of the distribution of the An 5f states to the ligand structural arrangement around the An sites.
作为对化学状态变化具有更高灵敏度的技术，对锕系元素M边的芯对芯（3d到4f）共振非弹性X射线散射（RIXS）和高能量分辨率荧光检测X射线吸收（HERFD-XAS）在三价锕系化合物中的应用进行了分析。例如，使用了一系列锕系氯化物AnCl（An = U、Np、Pu、Am、Cm、Bk和Cf）。应用晶体场多重态形式来计算3d - 4f RIXS图谱，并沿着入射能量轴在恒定发射能量（对应于RIXS强度最大值）处提取这些RIXS图谱的切片作为HERFD-XAS光谱。还研究了HERFD与传统XAS方法之间的关系。尽管三价锕系元素的An M HERFD图谱与传统XAS光谱之间存在一些差异，但计算结果表明，HERFD方法可用于An M边，以监测锕系元素化学状态的微小变化。总体而言，与An M边相比，在An M边发现HERFD和XAS光谱之间有更好的一致性。通过使用点电荷静电模型，研究了An M HERFD-XAS光谱对An配位数的依赖性，这表明An 5f态的分布对An位点周围配体结构排列具有显著的敏感性。
