Probing actinide bonding properties by computations and advanced X-ray spectroscopy

Actinide elements are important for several societal relevant topics, including nuclear medicine and the safe storage of nuclear waste. The study of actinide complexes is highly challenging. It is experimentally challenging due to the radioactivity of the actinides and theoretically challenging due to the presence of strongly correlated 5f-electrons, and relativistic effects. One open question raised in the actinide community is the correlation between bond covalency and stability, important for understanding the chemical and physical properties of the actinides, and their relationship with electronic structure theory or spectroscopic observables, However, in-depth rigorous analysis of the structural and bonding relationship for the actinide elements currently fail to meet the growing demand in the field. The scarcity of research data is particularly significant for transuranic elements. To obtain predictive understanding of the chemical and physical properties of the actinide elements, it is necessary to develop and apply advanced spectroscopic and theoretical tools.
In this presentation, actinide heteroarylalkenolate complexes used as a model system to develop theoretical spectroscopic approaches for probing the covalency of actinide-ligand bonds. ... mehrBesides conventional uranium L3 edge X-ray absorption near edge structure (XANES), the uranium M4,5-edge high energy resolution-X-ray absorption near edge structure (HR-XANES) and core-to-core resonant inelastic X-ray scattering (CC-RIXS) were applied to uranium heteroarylalkenolate complexes. In this work, beyond the conventional DFT method, the ab initio ligand field theory, for example: Ligand-Field Density Functional Theory (LFDFT) and Multiplet ligand-field theory, is also performed to understand and interpret the experimental discovery then investigate the bonding properties of actinide compounds. Coupling of advanced X-ray spectroscopic techniques with electronic structure calculations provide valuable insights into the importance of bond covalency for the strength of the chemical bond and the actinide reactivity.