Sputtering of water ice induced by C ₆₀ bombardment: Onset of plume formation

The interaction of a 5 keV C ₆₀ projectile with amorphous water ice is studied using molecular dynamics computer simulations. The energetic C ₆₀ molecule causes large-scale collisional events in the subsurface region, involving more than 10 ⁴ water molecules in a time of less than 3 ps. The energy deposited in the sample is sufficiently large to turn the ice into a superheated and superdense gas. The gas is expelled into the vacuum, leading to the formation of a flow that manifests itself in the angular and velocity distributions of emitted water molecules.