Identification of the neutral products from the unimolecular dissociation of singly and multiply charged C 60 fullerene ions

The neutral products eliminated upon the collisionally activated dissociation (CAD) of C   60 +zions ( z = 1–4) are post‐ionized to cations or anions and collected in neutral fragment‐reionization ( + N f R +,− ) mass spectra. These spectra provide conclusive evidence that the decompositions C   60 + z→ C   x + z+ C 2n (where x >30 and 2n < 30) proceed by cleavage of whole C 2n clusters, not consecutive losses of n C 2 . As teh charge of the fullerene precursor ion increases, the largest detectable neutral loss decreases, from C 28 for z = 1 to C 12 for z = 4. Post‐ionization of C 2n to cations preferentially produces odd‐carbon cluster ions (e.g., C 5 + , C 7 + , C 11 + , C + 15 ) whereas post‐ionization to anions yields abundant even‐carbon cluster ions (C 6 − , C 8 − ).