PNNL

Abstract

In the advent of the 2nd International Workshop on Advanced Techniques in Actinide Spec-troscopy (ATAS 2014), an inter-laboratory round-robin test (RRT) was initiated. The main goal of this RRT was the comprehensive molecular analysis of a simple aqueous complexing system – U(VI) acetate – which was selected to be independently investigated by various 100 spectroscopic (vibrational, luminescence, X-ray absorption, and nuclear magnetic resonance spectroscopy) and quantum chemical methods applied by leading laboratories in actinide or geochemical research. Ultimately, more than 40 scientists hosted at 20 institutions in 7 coun-tries participated. The outcome of this RRT were considered on two levels: First, conformities as well as 105 discrepancies in the results of each spectroscopic technique and their sources were evaluated. The raw data from the experimental approaches were found to be generally consistent. In particular, for complex setups such as accelerator-based X-ray absorption spectroscopy, the agreement between the raw data was surprisingly high. By contrast, the data obtained using luminescence spectroscopy turned out to be strongly related to the chosen acquisition param-110 eters. Second, the potentials and limitations of coupling various spectroscopic and, in partic-ular, theoretical approaches for the comprehensive study of actinide molecule complexes were assessed. The additional benefits of the combined approach with regard to the explora-tion of the aqueous speciation of the U(VI) acetate system were elaborated.