The triscarbonato uranyl solid phases containing alkaline (Alk = Na, K) alkaline earth (Ae = Mg, Ca) are known since mid-19th century. The evidence of equivalent complexes in solution Ca-UO2-CO3 has only occurred during the 1990s. Their importance is recognised as major in certain natural environments, from surface waters down to deep underground disposal sites of nuclear waste disposal. Using theoretical calculations, the formation of Alk-Ae-U(VI)-CO3 complexes has been proposed but without any experimental confirmation. This PhD work, in collaboration between Laboratory for Analytical, Nuclear, Isotopic, and Elementary development (DES/ISAS/DRMP/SPC/LANIE) in the Saclay centre, and the Laboratory for the Ligand Actinide Interactions (DES/ISEC/DMRC/SPTC/LILA) in the Marcoule centre, is proposing to couple the advantages of time-resolved fluorescence (or luminescence) of uranium(VI) complexes (LANIE) and theoretical calculations and X-ray spectroscopy (LILA) to guide the experiments to evidence the eventual Alk-Ae-U(VI)-CO3 complexes in solution.
The candidate must already dominate, or quickly acquire, a competence in solution chemistry with a strong tendency upon the acquisition of thermodynamic constants and functions of reactions, with a knowledge of the concepts linked to the ionic strength correction and SIT. Adaptability to, of even better knowledge, of different spectroscopic techniques will be an undeniably asset. The inclination to multidisciplinary team work will be essential.