Direct evidence for the sequential decay C-60(z+)->C-58(z+)->C-56(z+)->center dot center dot center dot

Using a two sector field mass spectrometer in combination with a crossed beams ion source we have obtained direct experimental evidence that C-60 fragment ions such as C-58,C-56,C-54,... produced by electron impact ionization of C-60 may be formed by unimolecular decay of the C-60 parent ion involving sequential loss of C? Moreover, by comparing experimental and theoretical breakdown graphs the overriding conclusion is that in the case of C-56(z+) production (with z = 1,2,3) sequential loss of two C-2 units dominates over the loss of a single C-4 unit.