Long-lived high-spin states of small anions: (II)-I-6 state of CO-

Stimulated by recent mass spectrometric observations, we have investigated several high-spin states of CO- to identify the observed anionic state. We follow a general construction principle for long-lived anionic states of sm all molecules: A possibly long-lived anionic state possesses several "equiv alent" valence electrons bound to a positively charged ion core. Applying t his idea to CO-, we have found a On state which is stable with respect to b oth single-electron emission and dissociation. Since all different decay ch annels are spin forbidden, this state is long-lived, and will be observable in a mass spectrometer. [S1050-2947(99)06504-X].