Resonant and nonresonant electron impact detachment of CN− and BO−

Abstract

Absolute cross sections for electron-impact detachment and electron-impact dissociation of CN− and BO− were measured for electron energies from threshold 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 section is discovered at an energy of ∼10 eV. No resonances were seen 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 Andersen et al. [Phys. Rev. Lett. 74, 892 (1995)].