Microscopic insights into the sputtering of thin organic films on Ag{111} induced by C ₆₀ and Ga bombardment

Molecular dynamics computer simulations have been employed to model the bombardment of Ag{111} covered with three layers of C ₆H ₆ by 15 keV Ga and C ₆₀ projectiles. The study is aimed toward examining the mechanism by which molecules are desorbed from surfaces by energetic cluster ion beams and toward elucidating the differences between cluster bombardment and atom bombardment. The results show that the impact of the cluster on the benzene-covered surface leads to molecular desorption during the formation of a mesoscopic scale impact crater via a catapulting mechanism. Because of the high yield of C ₆H ₆ with both Ga and C ₆₀, the yield enhancement is observed to be consistent with related experimental observations. Specific energy and angle distributions are shown to be associated with the catapult mechanism.