Valence shell relativistic configuration interaction calculations yield 15 bound states for ${\mathrm{Ce}}^{-}.$ These include eight $6p$ attachments calculated with respect to the ${4f5d6s}^2\hspace{0.5em}J=4\mathrm{}$ ground state with the following electron affinities (in meV with corresponding J in parentheses): 349 (9/2), 215 (7/2), 203 (5/2), 153 (7/2), 135 (3/2), 117 (11/2), 104 (9/2), and 53 (7/2). The remaining seven bound states are $5d$ attachments, treated as $6s$ attachments with respect to the excited ${4f5d}^{2}6sJ=8$ threshold, with the following electron affinities: 428 (7/2), 327 (9/2), 281 (9/2), 193 (11/2), 182 (7/2), 167 (9/2), and 149 (11/2). Core-valence effects were found to be minimal, and improvements with respect to our earlier work [K. Dinov, D. R. Beck, and D. Datta, Phys. Rev. A 50, 1144 (1994)] have been ascribed to better treatment of second order effects (in the case of the $6p$ attachments) and a more appropriate choice of neutral threshold (in the case of the $5d$ attachments).

• Received 6 October 1999

DOI:https://doi.org/10.1103/PhysRevA.61.034501