Precursor Mediated Cycloaddition Reaction of Ethylene to the Si(100)c(4 × 2) Surface

Abstract

We report the direct observation of a precursor state for the cycloaddition reaction (the di-σ bond formation) of ethylene on Si(100)c(4 × 2) using high-resolution electron energy loss spectroscopy at low temperature, and the meta-stable precursor state is identified as a weakly bonded π-complex type. The activation energy from the π-complex precursor to the di-σ bonded species is experimentally estimated to be 0.2 eV. First-principles calculations support the π-complex precursor mediated cycloaddition reaction of ethylene on Si(100)c(4 × 2).