We have optimized a new ReaxFF reactive force field parametrization for Cu-S, Cu-thiol and Cu-alkoxy to enable molecular dynamics simulations of the thermal and shear-induced reaction kinetics of OCH3 and SCH3 on copper surfaces. Based on previously-developed Cu-water ReaxFF parameters, Cu-S bond, valence angle, and torsional parameters were added and parameterized in order to reproduce accurate energy barriers for surface and sub-surface adsorption, heat of formation, and the crystal structure properties of CuS, CuS2, and Cu2S phases. In addition, the parameters for binding energy, adsorption and desorption, and decomposition of thiol and alkoxy molecules on the copper surfaces were included and optimized using density functional theory. This new force field has been used to study the tribochemistry of adsorbed thiolate and alkoxy species in a sliding copper interface. The reaction pathways for molecular decomposition and dissociation were followed to explore the shear-induced reactions.

Optimization of a ReaxFF reactive force field for modeling tribochemical reactions of Cu-S and Cu-thiol/ alkoxy systems

253rd National Meeting (2017)

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