The dimers stay intact: a quantitative photoelectron study of the adsorption system Si{100} (2x1)-C₂H₄

Abstract

Using the technique of photoelectron diffraction in the scanned energy mode we show that the Si dimer separation on the Si{100} surface following the adsorption of ethene (ethylene) is 2.36(±0:21) Å. This value is only very slightly larger than on the clean surface and shows that the dimer remains intact, thus providing a clear quantitative experimental resolution of a long controversy in the literature. The C-C and C-Si separations are 1.62±0.08 Å and 1.90 ± 0.01 Å, respectively, the former indicating a bond order of less than one.