High-resolution X-ray absorption spectroscopy as a probe of crystal-field and covalency effects in actinide compounds
2016 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, no 29, 8093-8097 p.Article in journal (Refereed) Published
Applying the high-energy resolution fluorescence-detection (HERFD) mode of X-ray absorption spectroscopy (XAS), we were able to probe, for the first time to our knowledge, the crystalline electric field (CEF) splittings of the 5f shell directly in the HERFD-XAS spectra of actinides. Using ThO2 as an example, data measured at the Th 3d edge were interpreted within the framework of the Anderson impurity model. Because the charge-transfer satellites were also resolved in the HERFD-XAS spectra, the analysis of these satellites revealed that ThO2 is not an ionic compound as previously believed. The Th 6d occupancy in the ground state was estimated to be twice that of the Th 5f states. We demonstrate that HERFD-XAS allows for characterization of the CEF interaction and degree of covalency in the ground state of actinide compounds as it is extensively done for 3d transition metal systems.
Place, publisher, year, edition, pages
2016. Vol. 113, no 29, 8093-8097 p.
actinide compounds, crystal field, covalency
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:uu:diva-302703DOI: 10.1073/pnas.1601741113ISI: 000380224500046PubMedID: 27370799OAI: oai:DiVA.org:uu-302703DiVA: diva2:967374