Theoretical Study of Electronic Structure of Pu(III-VI) Aqua Ions Using M4,5-Edge Resonant Inelastic X-Ray Scattering and High-Energy Resolution Spectroscopies

This presentation reports the study on the electronic structure and bonding properties of plutonium in aqueous solution, with special focus on the intera ctions between Pu and water ligand. An in depth understanding of the relationship between bonding properties and bond stability of Pu in various oxidation states is crucial for comprehending the environmental behavior of Pu, which has also significance for nucl ear waste management, fuel reprocessing, and environmental cleanup. Pu naturally exists in four oxidation states (III, IV, V, VI), which dictate its chemical pro perties and environmental fate. We prepared Pu aqueous solutions with different oxidation states ..And we analyzed them using advanced techniques: Pu M 4,5 edge resonant inelastic x ray scattering (RIXS) and high energy resolution x ray absorption near edge spectroscopies HR XANES ) both at the experimental and theoretical levels. Besides, we developed computati onal method, calculating RIXS maps with density functional theory an d ligand field model (LFDFT). LFDFT). This allows us to obtain ligand field parameters (Slater Condon integrals, spin orbit coupling constant and ligand field potential) without sc aling factors or empirical corrections. ... mehrThe results show very good agreement between experiments and theory, facilitating our spectral interpretation. This joint experiment theory effort provides insights into Pu ion s coor dination chemistry and local e lectronic structure, complementing standard UV visible spectroscopy and nucl ear magnetic resonance studies. We also aim at extracting long sought details on the Pu ligand bonding interaction, bond covalency and stability relationship, shedding light on the Pu solvation dynamics, and informing future studies on Pu ion stability under various environmental conditions and oxidation state monitoring.