论文标题
HEXS和HERFD XANES的应用，以精确的actinide纳米材料的结构表征：应用于THO2
The application of HEXS and HERFD XANES for accurate structural characterization of actinide nanomaterials: application to ThO2
论文作者
论文摘要
actinide纳米颗粒（NP）的结构表征至关重要且难以实现，尤其是对于NP低于3 nm的非均匀样品。通过将高能量X射线散射（HEX）和高能分辨率荧光结合，检测到X射线近边结构（HERFD XANES），我们首次表征了通过化学沉淀获得的短和中等范围的THO2 NPS。通过这种方法，可以在其形成过程的不同步骤中对NP的结构进行新颖的见解。配对分布函数（PDF）揭示了与Tho2小型单元相似的高浓度，类似于在形成的初始步骤中与1 nm THO2 NP混合的六聚体簇。在150 C处干燥沉淀物可促进最小单元重结晶成更热力学稳定的THO2 NP。 f态的直接探针在TH M4边缘的HERFD XANE显示出我们与TH原子周围局部对称性的破裂相关的变化，这很可能涉及表面原子。共同的HEX和HERFD是研究actinide NP及其形成机制的有力方法。
Structural characterization of actinide nanoparticles (NPs) is of primary importance and hard to achieve, especially for non-homogeneous samples with NPs below 3 nm. By combining High Energy X-ray Scattering (HEXS) and High-Energy-Resolution Fluorescence Detected X-ray Near-Edge Structure (HERFD XANES), we characterized for the first time both short- and medium-range order of ThO2 NPs obtained by chemical precipitation. With this methodology, a novel insight into the structure of NPs at different steps of their formation process is achieved. The Pair Distribution Function (PDF) reveals a high concentration of ThO2 small units similar to Th hexamer clusters mixed with 1 nm ThO2 NPs in the initial steps of formation. Drying the precipitates at 150 C promotes recrystallization of the smallest units into more thermodynamically stable ThO2 NPs. HERFD XANES at Th M4 edge, a direct probe of the f states, shows variations that we correlate to the break of the local symmetry around Th atoms, which most likely concerns surface atoms. Together, HEXS and HERFD are a powerful methodology to investigate actinide NPs and their formation mechanism.
