Adsorption energies on extended surfaces with CCSD(T) quality: ethylene on Si(001)

Abstract

We present a theoretical benchmark calculation for the prototypical surface chemical reaction of ethylene on silicon(001). State-of-the-art coupled cluster calculations with periodic boundary conditions (CCSD(T)<inf>pbc</inf>) are carried out on three stationary points of the potential energy surface carefully studying the convergence of all computational parameters. The comparison to a set of commonly used density functionals show two situations along the reaction coordinate. The reaction energy is quite well reproduced with most density functionals, dispersion-corrected hybrid functionals being the most accurate as often stated for adsorption of organic molecules on semiconductor surfaces. However, the reaction barriers show large deviations of around 50% compared to the benchmark value which requires more investigations in the future. We hope to spark these investigations and provide a starting point for more theoretical benchmark studies on surface chemical reactions with larger molecules in the future.