Controlled deposition, soft landing, and glass formation in nanocluster-surface collisions.

Molecular dynamics simulations have been used to investigate the dynamics and redistribution of energy during the impact of a nanocrystal with adsorbed liquid films. Although impact of a 32-molecule NaCl cluster on a solid surface at 3 kilometers per second leads to melting, disordering, fragmentation, and rebounding, the same size cluster colliding with a liquid neon film transfers its energy efficiently to the liquid for a controlled soft landing. Impact on a higher density film (argon) leads to rapid attenuation of the cluster velocity, accompanied by fast heating. Subsequent disordering, melting, and fast cooling by evaporation of argon quench the cluster to a glassy state. These results suggest a method for the controlled growth of nanophase materials.