Room temperature crystal field splitting of curium resolved by circularly polarized luminescence spectroscopy.

Coordination of Cm(iii) with a chiral decadentate ligand ,,','-tetrakis[(6-carboxypyridin-2-yl)methyl]-1,2-diaminocyclohexane (tpadac) generated complexes with strong luminescence allowing for the unprecedented measurement of well-resolved Cm(iii) circularly polarized luminescence spectra. Quantitative resolution of the electronic structure of the [Cm(tpadac)][K] complexes was achieved at room temperature, highlighting the strength of the combination of luminescence and circularly polarized luminescence spectroscopies to unravel the fundamental electronic structure of Cm(iii). These results are a clear demonstration that these spectroscopies are powerful yet simple tools for the fundamental understanding of electronic structure, which opens the door to future investigations of other Cm(iii) complexes in geometries relevant to nuclear applications, and even other 5f-elements.