Müller Alexander, Deblonde Gauthier J-P, Ercius Peter, Zeltmann Steven E, Abergel Rebecca J, Minor Andrew M
National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.
Nat Commun. 2021 Feb 11;12(1):948. doi: 10.1038/s41467-021-21189-1.
Due to their rarity and radioactive nature, comparatively little is known about the actinides, particularly those with atomic numbers higher than that of plutonium, and their compounds. In this work, we describe how transmission electron microscopy can provide comprehensive, safe, and cost-effective characterization using only single nanogram amounts of highly-radioactive, solid compounds. Chlorides of the rare elements berkelium and californium are dropcast and then converted in situ to oxides using the electron beam. The f-band occupancies are probed using electron energy loss spectroscopy and an unexpectedly weak spin-orbit-coupling is identified for berkelium. In contrast, californium follows a jj coupling scheme. These results have important implications for the chemistries of these elements and solidify the status of californium as a transitional element in the actinide series.
由于锕系元素及其化合物稀有且具有放射性，人们对它们的了解相对较少，尤其是那些原子序数高于钚的元素。在这项工作中，我们描述了透射电子显微镜如何仅使用单纳克量的高放射性固体化合物就能提供全面、安全且经济高效的表征。将稀有元素锫和锎的氯化物滴铸，然后利用电子束原位转化为氧化物。使用电子能量损失谱探测f带占据情况，并确定锫存在意外微弱的自旋轨道耦合。相比之下，锎遵循jj耦合方案。这些结果对这些元素的化学性质具有重要意义，并巩固了锎作为锕系元素系列中过渡元素的地位。
