Measurement of the electron affinity of cerium

The electron affinity of cerium has been measured using laser photodetachment electron spectroscopy. The electron affinity of Ce(1G4) was determined to be 0.955 +/- 0.026 eV. The data also show that Ce- has at least two bound excited states with binding energies of 0.921 +/- 0.025 eV and 0.819 +/- 0.027 eV relative to the (1G4) ground state of the cerium atom. The present experimental measurements are compared to recent calculations of the energy levels of Ce-. Strong disagreement with the most recent theoretical atomic structure calculations highlights the complicated nature of this particular lanthanide.