Description and Analysis of the Third Spectrum of Cerium (Ce iii)

New observations of the third spectrum of cerium from 757 to 11 091 Å are given, including 1700 lines not previously reported. The ground level of the ion is established as the 3H4 state of the 4f2 electronic configuration. One hundred twenty-six newly discovered energy levels are given, together with revised values of previously known levels. The ionization limit, at 161 955 cm−1, is derived from the three member 4f nd series.