Structural Origin of the Formation of Odd-Numbered Carbon Clusters from Fullerene Derivatives

We report the mass spectrometric investigation on fullerene derivatives C₆₀CH₂, C₆₀RH , C₆₀R₂(R = C₆H₅ CO-) and C₆₀O_n under the 308nm laser ablation. In the negative ion mass spectra of C₆₀CH₂, C₆₀R₂ and C₆₀O_n odd-numbered clusters C^-₅₇,C^-₅₅, C^-₅₃, C^-₅₁ are observed clearly in addition to the even-numbered fullerene fragment ions, while for the monoadduct C₆₀ RH,, odd-numbered species can not be detected. In the positive ion channel, the fragmentation patterns of the three derivatives are similar