Long-lived states of N-2(-): Formation, lifetimes, and identity

Long-lived metastable states of N-2(-) are generated by sputtering surfaces of TiN or BN with keV Cs+ ions. The lifetimes of the metastable ions have been measured at the storage ring ASTRID. Experimental investigations of th e charge exchange of N-2(+) ions in alkali-metal vapor and theoretical calc ulations support the conclusion that the long-lived N-2(-) species are sext et states, originating from the attachment of an electron to a quintet stat e of the N-2 molecule. [S1050-2947(99)07911-1].