CLUSTER-MOLECULE COLLISIONS - A MOLECULAR-DYNAMICS ANALYSIS OF A PICK-UP EXPERIMENT

The molecular dynamics technique has been used to simulate the interaction between a cold (2 K) argon cluster, Ar20, and a molecule, CH3CN. Two separate events have been examined: ( 1 ) The molecule was placed almost at rest on the surface of the duster. It stays on the surface for approximately 300 ps, at which point the duster melts and the molecule becomes solvated. (2) The molecule experienced a head-on collision with the duster. In this case, the cluster responded by melting immediately and the molecule moved below the surface within 40 ps of the collision. In both events the cluster retained the molecule throughout the simulation (almost-equal-to 1 ns); however, evaporation of a single argon atom was observed. The results are used to discuss "pick-up" experiments where mixed clusters have been prepared through collisional attachment of single atoms and molecules to clusters.