ELECTRON-AFFINITIES OF 6 BOUND-STATES OF CE- FORMED BY ATTACHMENT OF 6P AND 5D ELECTRONS TO CE

Valence-shell relativistic configuration-interaction calculations for Ce- (6p attachment to the 4f5d6s2 ground state) have yielded the following electron affinities (EA): (2J, EA (eV)) = (9, 0.259), (7, 0.147), (5, 0.105), (3, 0.043), and (7, 0.055). We also find the electron affinity for 5d attachment in the 4f5d(2)6s2 2J = 7 state to be 0.178 eV. This is possibly the second species (La- being the first) with opposite parity bound states. The existence of several bound states is consistent with the high yields of Ce- achieved in recent accelerator mass spectrometry experiments.