“…Prominent features of this series of spectra are the absorption bands associated with Pu(IV) (observed 648-662, 707, 790, 860, and 1075 nm) [15,18,[42][43][44] and Pu(VI) (observed 625, 817, 831, 857, 948, 983, and 1160 nm) [44][45][46]. The absorbance bands associated with Pu(IV) are attributed to Pu(NO 3 ) n 4-n nitrato complexes determined to be dominant below 5 M nitric acid [15,46,47].…”