DISSOCIATION OF SINGLY AND MULTIPLY-CHARGED FULLERENES - EMISSION OF C-4, OR SEQUENTIAL EMISSION OF C-2

We have obtained direct mass spectrometric evidence that fullerene ion s C-60(z+)(z = 1, 2, or 3) and C-58(z+) (z=1,2) undergo unimolecular d issociation by sequential emission of two C-2 units, on a time scale o f 10(-5) s. Moreover, a comparison of experimental and theoretical bre akdown graphs reveals that unimolecular formation of C-56(+) from the C-60(+) parent ion within a given observational time window is dominat ed by successive loss of C-2; direct C-4 loss does not contribute sign ificantly. This conclusion is not affected by uncertainties in our kno wledge of the energetics of C-2 vs C-4 loss. (C) 1997 American Institu te of Physics.