The Spectrum of Trebly Ionized Cerium

The spectrum of cerium has been photographed from λ3600 to λ500 Å by means of a two-meter grating of 30,000 lines per inch mounted in a vacuum spectrograph, using the vacuum spark and the spark in nitrogen as sources. An analysis of the spectrum of Ce IV results in the location of the 6S − 6P, 6P − 6D, 6P − 7S, 5D − 6P, 6P − 8S and possibly the 6P − 7D multiplets. The ionization potential is approximately 33.3 volts.