The spectrum of four-times ionized cerium Ce v has been observed with a sliding-spark discharge and a 10.7-m normal-incidence vacuum spectrograph. A total of 107 lines have been classified as transitions between 51 energy levels. All levels of the 5p6, 5p54f, 5p55d, 5p56s, 5p56p, and 5p56d configurations have been determined. Because of collapse of the 4f shell, the 5p54f configuration is situated well below 5p55d. Ab initio calculations and least-squares fits of the energy parameters to the experimental energy levels are reported. The ionization energy is revised to 527 100±2000 cm-1 (65.35±0.25 eV).
- Atom- och molekylfysik och optik (10302)