On the kinetic energy release distribution for C2 evaporation from fullerene ions

We present a critical evaluation of the kinetic energy released in the unimolecular dissociation of C-60(+), C-58(+), and C-56(+). High-quality kinetic energy release distributions (KERD) have been recorded in a three-sector-field mass spectrometer that is equipped with two electric sectors. Systematic errors arising from assumptions about the shape of the KERD are explored by a combination of experiments and simulations; an alternative to the 'model-free approach' is suggested. For decay of C-60(+), an average KER of 394 +/- 14 meV is obtained. Surprisingly, the experimental KER distributions are virtually indistinguishable from the one expected for a pure Langevin-type interaction. (C) 2004 Published by Elsevier B.V.