TY - JOUR
T1 - Local Symmetry Effects in Actinide 4f X-ray Absorption in Oxides
AU - Butorin, Sergei M.
AU - Modin, Anders
AU - Vegelius, Johan R.
AU - Suzuki, Michi To
AU - Oppeneer, Peter M.
AU - Andersson, David A.
AU - Shuh, David K.
N1 - Funding Information:
The work at the Advanced Light Source was supported by the Director, Office of Science, Office of Basic Energy Sciences, and this research (D.K.S.) was supported by the Director, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences Heavy Element Chemistry Program, both of the U.S. Department of Energy at Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231. P.M.O. acknowledges support from the Swedish Research Council (VR), the European Atomic Energy Community's FP7-work programme (Grant No. 269903, "REDUPP"), and the Swedish National Infrastructure for Computing (SNIC).
PY - 2016/5/3
Y1 - 2016/5/3
N2 - A systematic X-ray absorption study at actinide N6,7 (4f → 6d transitions) edges was performed for light-actinide oxides including data obtained for the first time for NpO2, PuO2, and UO3. The measurements were supported by ab initio calculations based on local-density-approximation with added 5f-5f Coulomb interaction (LDA+U). Improved energy resolution compared to common experiments at actinide L2,3 (2p → 6d transitions) edges allowed us to resolve the major structures of the unoccupied 6d density of states (DOS) and estimate the crystal-field splittings in the 6d shell directly from the spectra of light-actinide dioxides. The measurements demonstrated an enhanced sensitivity of the N6,7 spectral shape to changes in the compound crystal structure. For nonstoichiometric NpO2-x, the filling of the entire band gap with Np 6d states was observed thus supporting a phase coexistence of Np metal and stoichiometric NpO2 which is in agreement with the tentative Np-O phase diagram.
AB - A systematic X-ray absorption study at actinide N6,7 (4f → 6d transitions) edges was performed for light-actinide oxides including data obtained for the first time for NpO2, PuO2, and UO3. The measurements were supported by ab initio calculations based on local-density-approximation with added 5f-5f Coulomb interaction (LDA+U). Improved energy resolution compared to common experiments at actinide L2,3 (2p → 6d transitions) edges allowed us to resolve the major structures of the unoccupied 6d density of states (DOS) and estimate the crystal-field splittings in the 6d shell directly from the spectra of light-actinide dioxides. The measurements demonstrated an enhanced sensitivity of the N6,7 spectral shape to changes in the compound crystal structure. For nonstoichiometric NpO2-x, the filling of the entire band gap with Np 6d states was observed thus supporting a phase coexistence of Np metal and stoichiometric NpO2 which is in agreement with the tentative Np-O phase diagram.
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U2 - 10.1021/acs.analchem.5b04380
DO - 10.1021/acs.analchem.5b04380
M3 - Article
AN - SCOPUS:84966330702
VL - 88
SP - 4169
EP - 4173
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 8
ER -