Observation of chemical-fusion reactions of fullerenes in the negative-ion channel

We observed the phenomenon of chemical fusion of fullerenes in a laser-desorption mass-spectrometric investigation of adduct compounds ${\mathit{R}}_{\mathit{n}}$${\mathrm{C}}_{60}$ (R=${\mathrm{C}}_6$${\mathrm{H}}_5$${\mathrm{CH}}_2$ or ${\mathrm{C}}_9$${\mathrm{H}}_7$) in the negative-ion channel. The radicals were believed to play a key role in the formation of stable higher-mass fullerenes and doubly charged negative ions of ${\mathrm{C}}_{60}$ in the gas phase, in our case. These results imply that the heat of fusion has to be released by evaporating small even-numbered fragments or by collison with the radicals ruptured from the ${\mathrm{C}}_{60}$ cage.