Transferable Gaussian Attractive Potentials for Organic/Oxide Interfaces

Organic/oxide interfaces play an important role in many areas of chemistry and particular for lubrication corrosion. Molecular dynamics simulations are the method choice providing complementary insight to experiments. However, force fields used simulate interaction between molecules oxide surfaces tend capture only weak physisorption interactions, discarding stabilizing Lewis acid/base interactions. We here propose a simple complement straightforward molecular mechanics description based on “out-of-the-box” Lennard-Jones potentials electrostatic interactions: addition attractive Gaussian potential reactive sites surface heteroatoms adsorbed organic molecules, leading (GLJ) potential. The interactions four oxygenated amine with typical widespread hematite γ-alumina investigated. root mean square deviation (RMSD) all probed is 5.7 kcal/mol, which corresponds error 23% over hematite. On γ-alumina, RMSD 11.2 kcal/mol using single parameter five chemically inequivalent aluminum atoms. Applying GLJ simulation films demonstrates that mobility surfactants overestimated by simplistic LJ potential, while other qualitatively correct show strong structuration slow films, as could be expected from first-principles adsorption energies model head groups.