C60fragmentation in charge-changing collisions with slow Au+ions

Abstract

We investigated ionization and fragmentation of C{sub 60} in the charge-changing collisions of 2.0 keV/amu Au{sup +} ions with C{sub 60} molecules. We performed simultaneous measurements of product ions, the number of secondary electrons, and a charge-selected outgoing Au projectile. The production of C{sub 60}{sup +} ions was predominant in the single-electron capture (1-capture) process. In contrast, multifragmentation of C{sub 60} was predominant in the single-electron loss (1-loss) process. The multifragmentation was enhanced in the 1-loss process compared with the 1-capture process when the same number of electrons was emitted from C{sub 60}. This enhancement was also observed when a fast Si ion traveled close to a carbon nucleus [T. Majima et al., Phys. Rev. A 74, 033201 (2006)]. The 1-loss process of slow Au{sup +} ions is considered to occur closer to a carbon nucleus than does the 1-capture process. Multifragmentation of C{sub 60} is caused by internal electronic excitation although it is probably assisted by nuclear stopping when, at least, the electronic excitation of C{sub 60} is small.