Strong projectile dependence of C₆₀fragmentation by MeV-energy heavy ions

Abstract

Experimental results are presented for ionization and fragmentation of C60 bombarded by various projectile ions of H+, Li1,2+, B1,2+, O2+, Si1,2+, Ag2+ and Au3+ with velocities 0.9v0-3v0 (v0: Bohr velocity). Mass distributions of light fragment ions Cn+ (n = 1-12) are found to change drastically depending on the projectile species or atomic number Zp. The result indicates that multifragmentation of C60 takes place at small impact parameters where the projectile nuclear charge is less screened. It is found that for heavy projectiles multiple ionization is apt to occur and lighter fragment ions are produced predominantly. Assuming the multifragmentation caused by penetration of the projectile through C60, energy deposition to C60 is calculated, and internal energy and ionization degree of C60 after collisions are estimated. It is concluded that the final fragment pattern is governed by the internal energy.

C60fragmentation in charge-changing collisions with slow Au+ions

“…For the estimation of the internal electronic excitation energy, we used the knowledge that the total energy transferred to the electrons in a target molecule (E d ) is divided among the excited and purely ionized electrons with a certain partition rate, α, on average over impact parameter [3,[20][21][22][23]. Then, the internal electronic excitation energy E int is given by E int = (1 − α)E d and the energy transferred to the purely ionized electrons E ion is expressed by E ion = αE d .…”

“…In Table I the estimated values of E int are presented for n i = 2-7. We would like to point out that the fragment patterns for various projectile ions in the MeV region were found to be governed by E int estimated with α and β for each projectile and its velocity [3].…”

ZOscillations in Ion-Induced Fullerene Fragmentation

“…), energy losses of about 350 eV were observed [2]. Also, in MeV collisions, Tsuchida et al found indications for fragmentation due to electronic stopping [3].…”

Kinetic-energy release inN2fragmentation by charge-changing collisions of2-MeVMizuno1, Yamada2, Tsuchida3 et al. 2010Phys. Rev. A7050View full textAdd to dashboardCite

“…As the molecular fragmentation occurs predominantly from a dissociative excited state, it is important to measure KER in individual fragmentation channels because it carries direct information about the initial dissociative excited states [8,14]. The amount of electronic energy deposition into a target molecule is the essential quantity that characterizes the fragmentation of molecules ranging from diatomic [3] to polyatomic [15] and cluster particles [16].…”