Molecular dynamic simulations of the sputtering of multilayer organic systems

Sputtering of organic overlayers has been modeled using molecular dynamics computer simulations. The investigated systems are composed of benzene molecules condensed into one, two and three layers on an Ag{111} surface. The formed organic overlayers were bombarded with 4 keV Ar projectiles at normal incidence. The development of the collision cascade in the organic overlayer was investigated. The sputtering yield, mass, internal and kinetic energy distributions of ejected particles have been analyzed as a function of the thickness of the organic layer. The results show that all emission characteristics are sensitive to the variation of layer thickness. Although most of the ejected intact benzene molecules originate from the topmost layer, the emission of particles located initially in second and third layers is significant. The analysis indicates that the metallic substrate plays a dominant role in the ejection of intact organic molecules.