Absolute cross sections for electron-impact detachment and electron-impact
dissociation of CN- and BO- were measured for electron energies from thresh
old to 40 eV. With both ions we see only little dissociation when electron
detachment occurs. In the case of CN- a resonance in the detachment cross s
ection is discovered at an energy of similar to 10 eV. No resonances were s
een in the case of BO-. We argue that the resonance observed for CN- is due
to an excited state of the dianion. The nonresonant part of the detachment
cross section is found to follow the classical prediction given by Anderse
n [Phys. Rev. Lett. 74, 892 (1995)]. (C) 2001 American Institute of Physics
.