Molecular dynamics simulations of cluster-surface collisions: Mechanisms for monomer emission

Artikel i vetenskaplig tidskrift, 2001

Molecular dynamics simulations of (H2O)4094-clusters impacting with a velocity of 470 ms–1 in the normal direction on a graphite surface kept at 1400 K were performed. The aim was to clarify the behavior of water molecules and other small fragments emitted during the collision event. The results agree well with previous experimental studies and with the results of a thermokinetic model for evaporation of small fragments during cluster scattering. About 80% of the evaporating water molecules come in close contact with the hot surface, and their translational degrees of freedom are partly accommodated to the temperature of the surface, especially in the direction normal to the surface plane, leading to a high translational temperature in this direction. The results stress the importance of energy transfer from the hot surface to the cluster and explain the high translational temperature determined from experimental angular distributions.