Photodetachment Spectroscopy of Ce$^{-}$*

Tunable infrared and visible laser photodetachment spectroscopy has been performed on Ce$^{-}$ using a crossed laser-ion beam apparatus. The relative photodetachment cross section for neutral production was measured over the photon energy range 0.5 eV -- 2.6 eV. The spectrum shows several continuum threshold features and reveals five narrow peaks associated with negative ion resonances. The present measurements will be compared to recent theoretical [1] and experimental [2] results which are in significant disagreement on fundamental physical quantities such as the electron affinity of Ce and the ground state configuration of Ce$^{-}$. [1] S.M. O'Malley and D.R. Beck, Phys. Rev. A \textbf{61}, 034501 (2000); X. Cao and M. Dolg, Phys. Rev. A \textbf{69}, 042508 (2004). [2] V.T. Davis and J.S. Thompson, Phys. Rev. Lett. \textbf{88}, 073003 (2002).