Collision Dynamics of Argon Cluster Ions, Ar^+_n (n=3-23) : Molecular Dynamics Simulation Based on Diatomics-in-Molecules Method

The molecular dynamics method combined with a quantum mechanical calculation has been used to simulate the collision between an argon atom and an argon cluster ion, Ar^+_n(n=3-23), which contains a given amount of internal energy. Two pathways were observed; (i) Evaporation after collisional energy transfer to the internal degrees of freedom vs. (ii) fusion via complex formation. The total reaction cross sections were compared with those experimentally obtained. It is found that the branching fractions of the evaporation and the fusion depend critically on the internal energy and the impact parameter