Velocity correlated multifragmentation inC60-surface impact: Energy distributions and incidence angle dependences

Abstract

described within a scenario where Cn groups are statistically thermally emitted off an outgoing precursor away from the surface, as manifested by shifted Maxwellian flux distributions with only two parameters: kinetic energy per carbon atom associated with the center-of-mass velocity of the moving precursor and its temperature T. The best fitted parameters were found to be = 2.60 eV and kT= 0.86 eV. A distinct narrowing effect was observed for the incidence angle dependences of the C n fragments yield, going from C4 to C15 . The gradually decreasing angular width as a function of cluster size n was analyzed based on the assumption of isotropic, statistical fragments emission off an outgoing multifragmenting source the superhot precursor. The predicted 1 /n narrowing law was found to be in good agreement with the observed width effect and the two parameters , kT extracted from the independently measured kinetic-energy distributions. We conclude that both energy and angle distributions clearly demonstrate a statistical expansionlike, precursor-mediated multifragmentation mechanism.