Molecule-induced displacive reconstruction in a substrate surface: Ethylidyne adsorbed on Rh(111) studied by low-energy-electron diffraction

It is found for the first time that a molecule can induce a displacive reconstruction in the substrate on which it is adsorbed. This is observed in a refined structure determination of Rh(111)(2\ifmmode\times\else\texttimes\fi{}2)-${\mathrm{C}}_{2}$${\mathrm{H}}_{3}$, in which ${\mathrm{C}}_{2}$${\mathrm{H}}_{3}$ (ethylidyne) is adsorbed on the Rh(111) single-crystal surface. This result strengthens an earlier hypothesis that catalytic reactions are usually accompanied by distortions in the catalyst, which can profoundly affect reaction rates and selectivities.