Energy and angular distributions of secondary ions from a C60 surface induced by fast heavy ion impacts

We have measured energy and angular distributions of secondary ions emitted from a C-60 film target bombarded by 4-MeV Si-28(3+) ions by using a time-of-flight coincidence method. Fullerene-like secondary ions of C-60-2n(+) In and C-60+2n(+) (n = 1-5) as well C-60 ions and multiples of C-60 such as C-60N(+) (N = 2, 3) ions were observed strongly. It is found that the 60 angular distributions of Q ion are roughly symmetric with respect to the surface normal of the target. On the other 60 hand, the angular distribution of C-62 ions is found to be slightly inclined from the surface normal. The present result indicates that fullerene-like ions may be produced predominantly via the mechanism predicted by the pressure-pulse model developed for fast heavy ions. (C) 2003 Elsevier Science B.V. All rights reserved.