OBSERVATION OF THE DOUBLY CHARGED, GAS-PHASE FULLERENE ANIONS C602- AND C702-

The fullerenes exhibit a remarkable ability to accommodate excess negative charge. We have observed C60(2-) and C70(2-) in a Fourier transform ion cyclotron resonance mass spectrometer by laser desorption (1.064-mu-m) of raw fullerene material that had been extracted from soot produced from graphite rods. C60(2-) was distinguished from C30- by the relative abundances and m/z values of its isotopic ions. C60(2-) was distinguished from the double harmonic of C60- by selective ejection of C60-, selective excitation of C60(2-), and by a new and definitive method based upon comparing frequency shifts of singly and doubly charged ions as a function of ICR trapping voltage.