Revised Interpretation of the Spectrum of Singly-Ionized Neodymium (Nd II)

Abstract

Because of the confusion between two low odd levels 1218 cm-1 apart, the complete system of levels of Nd II built on the core f3 had to be revised with the help of the 144Nd-150Nd isotope shift. The lowest odd level f3d2 6M13/2 is now at 8009.810 cm-1, 96 levels have been shifted and 126 new levels have been found. The new identifications rely upon parametric studies of the sub-configurations 4f35d6s + 4f3(4I)5d2 + 4f4(5I)6p (115 interpreted levels) and 4f3(4I)5d6p + 4f3(4I)6s6p (124 interpreted levels).