Computational Study of Chemical Reactions and Material Modification during Polyatomic-Ion and Cluster-Surface Deposition

Susan Sinnott of the University of Florida is supported by the Theoretical and Computational Chemistry Program to examine particle-surface interactions that can lead to chemical reactions and material modification using molecular dynamics (MD) simulations. Three closely related problems will be studied. First, the deposition of covalently bound polyatomic ions on polymeric substrates will be examined. The unique capabilities of polyatomic ions for material modification and thin-film growth motivate this research, which aims to shed light on the analogous and more complex processes that take place in low-energy plasmas. Second, the use of polyatomic and single-atom ions to chemically functionalize and modify carbon nanotubes and nanotube-polymer interfaces will be explored, motivated by the fact that carbon nanotubes are being considered for use as fibers in the next generation of composite materials. Finally, the novel size-specific reactions that occur in gas solvent assisted chemistry when molecular clusters are deposited on solid surfaces will be studied, along with the growth of covalently balanced nanostructured thin films that can be generated experimentally through cluster-beam deposition. This project requires expansion and refinement of existing MD programs to include kinetic Monte Carlo simulations of thermal surface diffusion and relaxation between MD simulations of each cluster deposition event. Collaborative efforts are planned with experimentalists and theorists on all three projects.

This computational project has the potential to provide new understanding that will be important for industrial materials processing. For example, ion deposition can serve as a model for several aspects of thin-film growth through low energy plasmas, which is the leading industrial method for depositing polymer thin films under dry conditions. Organic thin films are important for optoelectronic applications, coatings, electronic devices, and mechanical applications. The present studies aim to model film deposition and surface modification issues relevant to ongoing experimental studies.