The distribution of fragments resulting from collisions between 50–200-keV ${\mathrm{C}}_{60}^{+}$ ions and ${\mathrm{H}}_2$ and He is found to follow approximately a simple power law I(m)=${\mathit{cp}}^{\mathit{m}}$ where p is a constant depending on both energy and target gas, and m is the number of missing ‘‘pairs’’ of carbon atoms. Based on this observation, a new dynamical fragmentation model involving the ratio of two characteristic times is proposed. In collisions by 300-keV ${\mathrm{C}}_{60}^{++}$ ions, the singly charged products are distributed quite differently, which implies the first evidence of the presence of charge-separation reactions.

• Received 26 June 1992

DOI:https://doi.org/10.1103/PhysRevLett.69.1915