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A theoretical study on collisions between fullerenes for the systems C + 60 + C 60 , C + 70 + C 60 and C + 70 + C 70 is presented covering a wide range of collision energies (50 < E < 250 eV in the centre-of-mass frame). Quantum molecular dynamics (QMD) simulations enable a detailed insight into the underlying mechanism of the different reaction channels. The fusion barriers for the investigated systems are determined and compared with experimental data taking into account the finite temperature of the colliding fullerenes. Structural as well as energetic aspects of the reaction mechanism are discussed from a microscopic point of view. As a counterpart to the QMD simulations, a simple phenomenological fusion model is described and compared to the experimental fusion cross section as a function of the collision energy.

Abstract. The dynamics of C6o-rare gas collisions is studied using molecular dynamics with empirical two-and three-body forces. The carbon potential is chosen to be able to reproduce the experimentally determined bond lengths and cluster radius of C6o as well as the structure of small carbon clusters. The reaction channels observed can be divided into four categories: deep inelastic scattering, fragmentation, capture and inelastic scattering. The temperature dependence of the threshold energy for capture is studied and compared with available experimental data. The calculations predict a maximum in the lowest tail of the kinetic-energy distribution of the projectile with a transition from a single-to a double-humped maximum with increasing collision energy and, in addition, may provide a natural interpretation for the, as yet unexplained, structure in the experimental shapes.

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Charge transfer and fragmentation in collisions of sodium cluster ions with caesium atoms have been investigated theoretically within a microscopic framework called Non-adiabatic Quantum Molecular Dynamics. To illustrate the complexity of non-adiabatic cluster collisions, in particular the interplay between charge transfer and fragmentation, Na + 4 (2.7 keV) + Cs collisions are studied in detail with special emphasis on methodical aspects. It is shown that integral and exclusive charge transfer cross sections can be understood only if all types of fragmentation processes including statistical decay are taken into account. The influence of the cluster structure (isomers, temperature, size) on measured and measurable cross sections is studied for different charge transfer channels as well as for fragmentation. In particular, cross sections for the exotic formation of caesium anions in such collisions are predicted.