CHEmistry, Spectroscopy and Speciation of protactinium – CHESS

Protactinium, a radioelement with unknown chemistry, is a key element : first actinide for which the 5f orbitals can be involved in chemical bonding, it is also naturally ocurring in envrionment, in the nuclear fuel cycle and also appear in the synthesis of innovative isotopes for medicine. Understanding the chemical behaviour of Pa in these compartments constitutes a great challenge especially since the basic chemistry of this element remains quite blurred ! In this project, we propose to switch to a new paradigm: "predict then experiment". Two main types of properties will be scrutinized, reactivity in terms of equilibrium constants between a set of ligands and protactinium(IV/V) and spectroscopy of protactium compounds. After an extensive methodological study and state-of-the-art theoretical predictions, we will set up prime electromigration, solvent extraction and spectroscopy (high-resolution XANES and laser spectrofluorimetry) experiments aiming at validating/improving the theoretical models and revealing this rare chemistry.