C₂ adsorption on the (100) diamond surface: periodic and large cluster calculations

Abstract

The adsorption of C₂ on the diamond (100) surface was studied using large clusters and periodic calculations at several levels of theory, including density functional based tight binding (DFTB), B3LYP and MP2. This reaction plays an important role in mechanisms of nanocrystalline diamond growth in hydrogen-poor plasmas. For C₂ adsorption on a single surface dimer, a C₉H₁₂ cluster was found to be sufficient to produce converged adsorption energies. Adsorption structures across two surface dimers are the most stable and require cluster sizes of at least C₃₆H₃₆ to take into account energy contributions due to substrate strain.