ABSORPTION SPECTRUM OF NPO2+2 IN CSUO2(NO3)3

The absorption spectrum of NpO2+2 doped in CsUO2(NO3)3 has been studied from 5000 to 22 000 cm-1. Nine electronic levels have been identified through their vibronic patterns and magnetic properties. Four of these levels, at 6458, 9420, 17 841, and 20 815 cm-1, are identified as pure electronic excitations within the 5f1 configuration. The other five electronic levels at 13 914, 16 071, 16 093, 17 968, and 21 021 cm-1 arise from the excited configuration consisting of two 5f electrons and a hole in the bonding electrons. The observed Zeeman effect of the absorption lines at 6458, 9420, 17 841, and 20 815 cm-1 agrees roughly with the calculation reported by Eisenstein and Pryce on the spectrum of NpO2+2 doped in RbUO2(NO3)3, whose crystal structure is isomorphous to that of CsUO2(NO3)3. © 1969 The American Physical Society.