TY - JOUR
T1 - Crystal-Field and Covalency Effects in Uranates
T2 - An X-ray Spectroscopic Study
AU - Butorin, Sergei M.
AU - Kvashnina, Kristina O.
AU - Smith, Anna L.
AU - Popa, Karin
AU - Martin, Philippe M.
N1 - Accepted Author Manuscript
PY - 2016
Y1 - 2016
N2 - The electronic structure of UV- and UVI-containing uranates NaUO3and Pb3UO6was studied by using an advanced technique, namely X-ray absorption spectroscopy (XAS) in high-energy-resolution fluorescence-detection (HERFD) mode. Due to a significant reduction in core–hole lifetime broadening, the crystal-field splittings of the 5f shell were probed directly in HERFD-XAS spectra collected at the U 3d edge, which is not possible by using conventional XAS. In addition, the charge-transfer satellites that result from U 5f–O 2p hybridization were clearly resolved. The crystal-field parameters, 5f occupancy, and degree of covalency of the chemical bonding in these uranates were estimated by using the Anderson impurity model by calculating the U 3d HERFD-XAS, conventional XAS, core-to-core (U 4f–3d transitions) resonant inelastic X-ray scattering (RIXS), and U 4f X-ray photoelectron spectra. The crystal field was found to be strong in these systems and the 5f occupancy was determined to be 1.32 and 0.84 electrons in the ground state for NaUO3and Pb3UO6, respectively, which indicates a significant covalent character for these compounds.
AB - The electronic structure of UV- and UVI-containing uranates NaUO3and Pb3UO6was studied by using an advanced technique, namely X-ray absorption spectroscopy (XAS) in high-energy-resolution fluorescence-detection (HERFD) mode. Due to a significant reduction in core–hole lifetime broadening, the crystal-field splittings of the 5f shell were probed directly in HERFD-XAS spectra collected at the U 3d edge, which is not possible by using conventional XAS. In addition, the charge-transfer satellites that result from U 5f–O 2p hybridization were clearly resolved. The crystal-field parameters, 5f occupancy, and degree of covalency of the chemical bonding in these uranates were estimated by using the Anderson impurity model by calculating the U 3d HERFD-XAS, conventional XAS, core-to-core (U 4f–3d transitions) resonant inelastic X-ray scattering (RIXS), and U 4f X-ray photoelectron spectra. The crystal field was found to be strong in these systems and the 5f occupancy was determined to be 1.32 and 0.84 electrons in the ground state for NaUO3and Pb3UO6, respectively, which indicates a significant covalent character for these compounds.
KW - computational chemistry
KW - crystal-field studies
KW - electronic structure
KW - uranium
KW - X-ray absorption spectroscopy
UR - http://resolver.tudelft.nl/uuid:5b6f2d4b-63e0-4540-8a31-ee8674724728
UR - http://www.scopus.com/inward/record.url?scp=84973305003&partnerID=8YFLogxK
U2 - 10.1002/chem.201505091
DO - 10.1002/chem.201505091
M3 - Article
AN - SCOPUS:84973305003
SN - 0947-6539
VL - 22
SP - 9693
EP - 9698
JO - Chemistry: A European Journal
JF - Chemistry: A European Journal
IS - 28
ER -