Fig. 3. Fourier transform of room temperature solution-phase An^III L₃-edge k³-EXAFS spectra of An^III (An = Cm^III, left; Am^III, middle; Ac^III, right) cations dissolved in HNO₃ (0.05 M, top, blue trace; 4 M, middle, red trace; 16 M, bottom, green trace). Fits to the data are shown as dashed black traces and scattering pathway contributions to the fit have been plotted inversely. The dilute HNO₃ system (0.05 M) was modeled with a single H₂O scattering pathway (cyan trace). The concentrated HNO₃ system (16 M) was modeled with scattering pathways from O_H2O (purple trace), O_NO3(bound) (olive trace), N_NO3 (orange trace), and O_{NO3(terminal)} (pink trace). Additionally, two multiple scattering paths were included, a three competent pathway labeled MS_3-comp (An^III → O_{NO3(terminal)} → N_NO3 → An^III; blue-green traces) and a four component pathway labeled MS_4-comp (An^III → N_NO3 → O_{NO3(terminal)} → N_NO3 → An^III, grey trace). The intermediate HNO₃ (4 M) data were modeled using a combination of fits for dilute HNO₃ (0.05 M, cyan scattering pathway) and concentrated HNO₃ (16 M; purple, olive, pink, orange, blue-green, and grey scattering pathways) spectra.