Molecular Dynamics Simulations of Hydrocarbon Film Growth from Acetylene Monomers and Radicals: Effect of Substrate Temperature

Abstract

In an attempt to rationalize the mechanisms occurring during plasma polymerization of acetylene, classical molecular dynamics computer simulations investigating the deposition and reaction of a mixed gas of acetylene molecules and radicals on the Ag(111) substrate were performed for a wide range of substrate temperatures. Prior to that, this article establishes a methodology for film deposition and identifies the appropriate potentials for hydrocarbons by comparison with electronic calculations using density functional theory. On the basis of this preliminary study, simulations of film growth are carried out at different temperatures using the reactive empirical bond order potential. Our results show that the rates of formation of new C–C and C–H bonds are higher at the beginning of the film growth when the substrate is still exposed than when it is covered with polymeric chains, and these initial reaction rates are proportional to temperature. The analysis of the hybridization of carbon atoms in the film...