Infrared photodetachment of Ce-: Threshold spectroscopy and resonance structure

摘要

The negative ion of cerium is investigated using tunable laser photodetachment threshold spectroscopy. The relative cross section for photodetachment from Ce- is measured over the photon energy range 0.61-0.75 eV using a crossed laser-beam-ion-beam technique. The spectrum of neutral atom production reveals a photodetachment threshold at 0.65 eV, which is interpreted as the threshold for the Ce- (4f5d(2)6s(2) H-4(7/2)) to Ce (4f5d6s(2) (1)G(4)) ground-state to ground-state transition yielding the electron affinity of Ce to be 0.65(3) eV. At least five narrow peaks are observed in the cross section over the range 0.62-0.70 eV due to negative ion resonances, and their energies and widths are measured. The results are compared to other recent experimental and theoretical studies of Ce-.